Illinois: Individual County Chronologies

Illinois Atlas of Historical County Boundaries

John H. Long, Editor; Peggy Tuck Sinko, Associate Editor; Gordon DenBoer, Historical Compiler; Douglas Knox, Book Digitizing Director and Digital Compiler; Emily Kelley, Research Associate; Laura Rico-Beck, GIS Specialist; Peter Siczewicz, ArcIMS Interactive Map Designer; Robert Will, Cartographic Assistant

Copyright The Newberry Library 2008

ADAMS

13 Jan 1825
ADAMS created from PIKE and Non-County Area 3 attached to PIKE. HANCOCK attached to ADAMS "for county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
03 Aug 1829
HANCOCK fully organized, detached from ADAMS. (Scofield, 679)
03 Mar 1837
ADAMS boundaries were extended to the middle of the Mississippi River [not mapped]. (Ill. Laws 1836-1837, pp. 91-92)
11 Feb 1843
ADAMS lost to creation of MARQUETTE (later HIGHLAND, extinct). (Ill. Laws 1842-1843, pp. 77-83)
27 Feb 1847
ADAMS lost to HIGHLAND (extinct). (Ill. Laws 1846-1847, gen., pp. 38-41)
by 31 Dec 1848
ADAMS gained all of HIGHLAND (extinct) when HIGHLAND failed to become fully organized as a county; HIGHLAND eliminated. (Wilcox, David F., 1:119-120)

ALEXANDER

04 Mar 1819
ALEXANDER created from Non-County Area 1 attached to UNION. (Ill. Laws 1819, pp. 113-114)
05 Jun 1843
ALEXANDER lost to creation of PULASKI. (Ill. Laws 1842-1843, pp. 99-101)

ALLEN (proposed)

27 Feb 1841
Legislature authorized creation of ALLEN (proposed) from MACOUPIN, MORGAN, and SANGAMON, dependent on local referendum that failed. Subsequent attempts were made to create a county in the same general area (BENTON in 1843 and OREGON in 1851), but all atte (Ill. Laws 1840-1841, pp. 87-90)

AUDUBON (proposed)

06 Feb 1843
Legislature authorized creation of AUDUBON (proposed) from FAYETTE, MONTGOMERY, and SHELBY, dependent on local referendum that failed. (Ill. Laws 1842-1843, pp. 73-74)

BENTON (proposed)

04 Mar 1843
Legislature authorized creation of BENTON (proposed) from GREENE, MACOUPIN, and MORGAN, dependent on local referendum that failed. Other attempts to create counties in the same general area (ALLEN in 1841; OREGON in 1851) were also unsuccessful. (Ill. Laws 1842-1843, pp. 104-108)

BOND

04 Jan 1817
BOND created by Illinois Territory from MADISON; BOND included territory in present Illinois, Wisconsin, and Michigan. (Ill. Terr. Laws, 254-256)
03 Dec 1818
BOND lost all territory in present Michigan and Wisconsin to Michigan Territory when the state of Illinois was created from Illinois Territory; BOND became a county in the state of Illinois. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
30 Jan 1821
BOND lost to creation of SANGAMON. (Ill. Laws 1820-1821, pp. 45-46)
31 Jan 1821
BOND lost to creation of PIKE. (Ill. Laws 1820-1821, p. 59)
12 Feb 1821
BOND lost to creation of MONTGOMERY. (Ill. Laws 1820-1821, pp. 142-143)
14 Feb 1821
BOND lost to creation of FAYETTE. (Ill. Laws 1820-1821, pp. 164-167)
27 Dec 1824
BOND lost to creation of CLINTON. (Ill. Laws 1824-1825, pp. 27-30)
19 Feb 1841
Legislature authorized BOND to gain from MADISON the eastern halves of townships 4 to 6 north, range 5 west, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, p. 80)
02 Mar 1843
BOND gained from MADISON. (Ill. Laws 1842-1843, pp. 98-99)

BOONE

04 Mar 1837
BOONE created from WINNEBAGO. (Ill. Laws 1836-1837, pp. 96-100)
02 Mar 1839
Legislature authorized BOONE to gain from McHENRY townships 43 to 46 north, range 5 east, dependent on local referendum that failed [no change]. (Ill. Laws 1838-1839, p. 242)
22 May 1843
BOONE gained from WINNEBAGO. (Ill. Laws 1842-1843, p. 92)

BROWN

01 Feb 1839
BROWN created from SCHUYLER. (Ill. Laws 1838-1839, pp. 52-55)

BUREAU

03 Apr 1837
BUREAU created from PUTNAM. (Ill. Laws 1836-1837, pp. 93-95)
19 Jan 1839
BUREAU gained all of Non-County Area 8 (remnant of JO DAVIESS and non-county area previously attached to LA SALLE); Non-County Area 8 eliminated. (Ill. Laws 1838-1839, pp. 43-45)
02 Mar 1839
BUREAU gained from PUTNAM. (Ill. Laws 1838-1839, p. 229)

CALHOUN

10 Jan 1825
CALHOUN created from PIKE. (Ill. Laws 1824-1825, pp. 65-67)

CARROLL

22 Feb 1839
CARROLL created from JO DAVIESS. (Ill. Laws 1838-1839, pp. 160-162)
27 Feb 1841
Legislature authorized CARROLL to gain from OGLE the eastern halves of townships 23 to 25 north, range 7 east, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, p. 90)

CASS

17 Apr 1837
CASS created from MORGAN. (Ill. Laws 1836-1837, pp. 101-103; Ill. Laws 1837, spec. sess., pp. 48-50)
04 Mar 1843
Legislature authorized CASS to gain from MORGAN the southern half of township 17 north all along its southern border, dependent on local referendum that failed [see 5 May 1845; no change]. (Ill. Laws 1842-1843, pp. 104-108)
05 May 1845
CASS gained from MORGAN. (Ill. Laws 1844-1845, pp. 313-315)

CHAMPAIGN

20 Feb 1833
CHAMPAIGN created from VERMILION and Non-County Area 4 attached to VERMILION. (Ill. Laws 1832-1833, priv., pp. 28-30)
14 Feb 1855
Legislature authorized creation of HARRISON (proposed) from CHAMPAIGN, McLEAN, and Non-County Area 4 attached to VERMILION, dependent on local referendum that failed [no change]. (Ill. Laws 1855, pub., pp. 113-117)
31 Jan 1857
Legislature authorized creation of HOLMES (proposed) from CHAMPAIGN, VERMILION, and Non-County Area 4 attached to VERMILION, dependent on local referendum that failed [no change]. (Ill. Laws 1857, pub., pp. 93-98)
13 Feb 1857
Legislature authorized creation of DOUGLAS (proposed) from CHAMPAIGN and COLES, dependent on local referendum that failed [no change]. (Ill. Laws 1857, pub., pp. 71-74)
09 Jul 1867
Legislature authorized creation of LINCOLN (proposed) from CHAMPAIGN and VERMILION, dependent on local referendum that failed [no change]. (Ill. Laws 1867, priv., 1:868-873)

CHRISTIAN

15 Feb 1839
DANE (now CHRISTIAN) created from MONTGOMERY and SANGAMON. (Ill. Laws 1838-1839, pp. 104-107)
26 Feb 1839
DANE (now CHRISTIAN) gained from SHELBY. (Ill. Laws 1838-1839, pp. 187-188)
01 Feb 1840
DANE renamed CHRISTIAN. (Ill. Laws 1839-1840, spec. sess., p. 80)
15 Feb 1851
Legislature authorized SHELBY to gain from CHRISTIAN township 11 north, range 1 east, dependent on local referendum that failed [no change]. (Ill. Laws 1851, gen., pp. 118-119)

CLARK

22 Mar 1819
CLARK created from CRAWFORD. (Ill. Laws 1819, pp. 166-167)
31 Jan 1821
CLARK lost to creation of PIKE. (Ill. Laws 1820-1821, p. 59)
14 Feb 1821
CLARK lost to creation of FAYETTE. (Ill. Laws 1820-1821, pp. 164-167)
23 Dec 1822
CLARK gained small area from CRAWFORD. (Ill. Laws 1822-1823, p. 79)
03 Jan 1823
CLARK lost to creation of EDGAR and to creation of Non-County Area 4. (History of Edgar, 514-515; Ill. Laws 1822-1823, pp. 74-75)
18 Jan 1826
CLARK lost to creation of VERMILION and lost to Non-County Area 4. (Ill. Laws 1826, pp. 50-53)
25 Dec 1830
CLARK lost to creation of COLES. (Ill. Laws 1830-1831, pp. 59-61)

CLAY

23 Dec 1824
CLAY created from CRAWFORD, FAYETTE, LAWRENCE, and WAYNE. (Ill. Laws 1824-1825, pp. 18-20)
15 Feb 1831
CLAY lost to creation of JASPER. JASPER not fully organized, part attached to CLAY until "organized." (Ill. Laws 1830-1831, pp. 50-52)
19 Dec 1834
JASPER fully organized, detached from CLAY. (Ill. Laws 1834-1835, pp. 154-155)
07 Jun 1841
CLAY lost to creation of RICHLAND. (Ill. Laws 1840-1841, pp. 77-79)
21 Feb 1863
Legislature authorized CLAY to gain from WAYNE the southern half of township 2 north, ranges 5 to 8 east, dependent on local referendum that failed [no change]. (Ill. Laws 1863, pub., pp. 84-85)

CLINTON

27 Dec 1824
CLINTON created from BOND, FAYETTE, and WASHINGTON. (Ill. Laws 1824-1825, pp. 27-30)

COFFEE (proposed)

01 Mar 1837
Legislature authorized creation of COFFEE (proposed) from HENRY, KNOX, and PUTNAM, dependent on local referendum that failed. COFFEE was in the same general area as STARK, created 2 March 1839. (Ill. Laws 1836-1837, pp. 86-88)

COLES

25 Dec 1830
COLES created from CLARK and EDGAR. (Ill. Laws 1830-1831, pp. 59-61)
01 May 1843
COLES lost to creation of CUMBERLAND. (Ill. Laws 1842-1843, pp. 94-98)
13 Feb 1857
Legislature authorized creation of DOUGLAS (proposed) from COLES and CHAMPAIGN, dependent on local referendum that failed [no change]. (Ill. Laws 1857, pub., pp. 71-74)
21 Mar 1859
COLES lost to creation of DOUGLAS. (Ill. Laws 1859, pub., pp. 24-29)

COOK

15 Jan 1831
COOK created from PUTNAM. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
12 Jan 1836
COOK lost to creation of WILL. (Ill. Laws 1835-1836, pp. 262-263)
16 Jan 1836
COOK lost to creation of McHENRY. McHENRY not fully organized, attached to COOK until "organized." (Ill. Laws 1835-1836, pp. 273-278)
01 Mar 1837
McHENRY fully organized, detached from COOK. (Ill. Laws 1836-1837, pp. 89-90)
02 Mar 1837
Legislature authorized creation of MICHIGAN (proposed) from COOK, dependent on local referendum that failed [no change]. (Ill. Laws 1836-1837, pp. 82-83)
09 Feb 1839
COOK lost to creation of DU PAGE. (Ill. Laws 1838-1839, pp. 73-74)

CRAWFORD

31 Dec 1816
CRAWFORD created by Illinois Territory from EDWARDS; CRAWFORD included territory in present Illinois, Wisconsin, and Michigan. (Ill. Terr. Laws, 247-249)
03 Dec 1818
CRAWFORD lost all territory in present Michigan and Wisconsin to Michigan Territory when the state of Illinois was created from Illinois Territory; CRAWFORD became a county in the state of Illinois. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
22 Mar 1819
CRAWFORD lost to creation of CLARK. (Ill. Laws 1819, pp. 166-167)
16 Jan 1821
CRAWFORD lost to creation of LAWRENCE. (Ill. Laws 1820-1821, pp. 16-17)
14 Feb 1821
CRAWFORD lost to creation of FAYETTE. (Ill. Laws 1820-1821, pp. 164-167)
23 Dec 1822
CRAWFORD lost small area to CLARK. (Ill. Laws 1822-1823, p. 79)
23 Dec 1824
CRAWFORD lost to creation of CLAY. (Ill. Laws 1824-1825, pp. 18-20)
15 Feb 1831
CRAWFORD lost to creation of EFFINGHAM and JASPER. EFFINGHAM and JASPER not fully organized, parts attached to CRAWFORD until "organized." (Ill. Laws 1830-1831, pp. 50-52)
20 Dec 1832
EFFINGHAM fully organized, detached from CRAWFORD. (Ill. Laws 1832-1833, pp. 22-23)
19 Dec 1834
JASPER fully organized, detached from CRAWFORD. (Ill. Laws 1834-1835, pp. 154-155)

CUMBERLAND

01 May 1843
CUMBERLAND created from COLES. (Ill. Laws 1842-1843, pp. 94-98)

DANE (see CHRISTIAN)

DE KALB

01 May 1837
DE KALB created from KANE. (Ill. Laws 1836-1837, pp. 96-100)

DE WITT

01 Mar 1839
DE WITT created from McLEAN and MACON. (Ill. Laws 1838-1839, pp. 199-201)
27 Jan 1841
DE WITT lost to creation of PIATT. (Ill. Laws 1840-1841, pp. 71-74)
26 Feb 1845
DE WITT lost to LOGAN. (Ill. Laws 1844-1845, p. 189)

DOUGLAS (proposed)

13 Feb 1857
Legislature authorized creation of DOUGLAS (proposed) from CHAMPAIGN and COLES, dependent on local referendum that failed. DOUGLAS was created, with slightly different boundaries, on 21 March 1859. (Ill. Laws 1857, pub., pp. 71-74)

DOUGLAS

21 Mar 1859
DOUGLAS created from COLES. An earlier attempt on 13 February 1857 to create DOUGLAS, with slightly different boundaries, failed [see DOUGLAS (proposed)] . (Ill. Laws 1859, pub., pp. 24-29)

DU PAGE

09 Feb 1839
DU PAGE created from COOK. On 2 March 1837, an unsuccessful attempt was made to create MICHIGAN (proposed) in the same general area. (Ill. Laws 1838-1839, pp. 73-74)
Aug 1839
The legislature authorized DU PAGE to gain from WILL the northern half of township 37 north, ranges 9 and 10 east, dependent on local referendum that failed [no change]. (History of Will, 358-359; Ill. Laws 1838-1839, pp. 73-74)

EDGAR

03 Jan 1823
EDGAR created from CLARK. Non-County Area 4 attached to EDGAR for administrative and judicial purposes. (History of Edgar, 514-515; Ill. Laws 1822-1823, pp. 74-75)
13 Jan 1825
EDGAR lost part of attached Non-County Area 4 to creation of PUTNAM. (Ill. Laws 1824-1825, pp. 85-87, 92-96)
18 Jan 1826
Part of Non-County Area 4 attached to EDGAR lost to creation of VERMILION; remainder of Non-County Area 4 was detached from EDGAR, attached to VERMILION. (Ill. Laws 1826, pp. 50-53)
25 Dec 1830
EDGAR lost to creation of COLES. (Ill. Laws 1830-1831, pp. 59-61)

EDWARDS

28 Nov 1814
EDWARDS created by Illinois Territory from GALLATIN and MADISON; EDWARDS included parts of present Illinois, Wisconsin, Michigan, and a small area of Indiana. (Ill. Terr. Laws, 128-130)
11 Dec 1816
EDWARDS exchanged small areas along the Wabash River with the state of Indiana (created this date), establishing the boundary between the present states of Illinois and Indiana. (U.S. Stat., vol. 3, ch. 57 [1816], secs. 1-2/pp. 289-291, and res. 1 [1816]/pp. 399-400; Van Zandt, 115)
31 Dec 1816
EDWARDS lost to creation of CRAWFORD; EDWARDS eliminated from present Wisconsin and Michigan. (Ill. Terr. Laws, 247-249)
03 Dec 1818
EDWARDS became a county in the state of Illinois when Illinois was created from Illinois Territory with present boundaries. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
26 Mar 1819
EDWARDS lost to creation of JEFFERSON and WAYNE. (Ill. Laws 1819, pp. 268-269)
29 Mar 1819
EDWARDS lost to JEFFERSON. (Ill. Laws 1819, pp. 320-321)
16 Jan 1821
EDWARDS lost to creation of LAWRENCE. (Ill. Laws 1820-1821, pp. 16-17)
27 Dec 1824
EDWARDS lost to creation of WABASH. (Ill. Laws 1824-1825, pp. 25-27)
22 Jan 1829
EDWARDS boundaries were clarified [no change]. (Ill. Rev. Code 1828-1829, p. 32)

EFFINGHAM

15 Feb 1831
EFFINGHAM created from CRAWFORD and FAYETTE; EFFINGHAM not fully organized, parts attached to CRAWFORD and FAYETTE until "organized." (Ill. Laws 1830-1831, pp. 50-52)
20 Dec 1832
EFFINGHAM fully organized, detached from CRAWFORD and FAYETTE. (Ill. Laws 1832-1833, pp. 22-23)
26 Feb 1845
Legislature authorized EFFINGHAM to gain from SHELBY the northern half of township 9 north, ranges 4 to 6 east, dependent on local referendum that failed [no change]. (Ill. Laws 1844-1845, p. 164)

FAYETTE

14 Feb 1821
FAYETTE created from BOND, CLARK, CRAWFORD, JEFFERSON, and WAYNE. (Ill. Laws 1820-1821, pp. 164-167)
24 Jan 1823
FAYETTE lost to creation of MARION. (Ill. Laws 1822-1823, pp. 49-50)
23 Dec 1824
FAYETTE lost to creation of CLAY. (Ill. Laws 1824-1825, pp. 18-20)
27 Dec 1824
FAYETTE lost to creation of CLINTON. (Ill. Laws 1824-1825, pp. 27-30)
23 Jan 1827
FAYETTE lost to MONTGOMERY, lost to creation of SHELBY, and lost to creation of Non-County Area 7. (Ill. Rev. Code 1826-1827, pp. 115-117)
15 Feb 1831
FAYETTE lost to creation of EFFINGHAM. EFFINGHAM not fully organized, part attached to FAYETTE until "organized." (Ill. Laws 1830-1831, pp. 50-52)
20 Dec 1832
EFFINGHAM fully organized, detached from FAYETTE. (Ill. Laws 1832-1833, pp. 22-23)
06 Feb 1843
Legislature authorized creation of AUDUBON (proposed) from FAYETTE, MONTGOMERY, and SHELBY, dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 73-74)

FORD

05 Apr 1859
FORD created from all of Non-County Area 4 attached to VERMILION; Non-County Area 4 eliminated. An earlier attempt to create HOLMES (proposed), on 31 January 1857 in the same general area, was unsuccessful. (Ill. Laws 1859, pub., pp. 29-33)

FRANKLIN

02 Jan 1818
FRANKLIN created by Illinois Territory from GALLATIN, JOHNSON, and WHITE. (Ill. Terr. Laws, 290-291)
03 Dec 1818
FRANKLIN became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
01 Mar 1835
FRANKLIN exchanged with PERRY. (Ill. Laws 1834-1835, pp. 36-37)
05 Aug 1839
FRANKLIN lost to creation of WILLIAMSON. (Ill. Laws 1838-1839, pp. 110-113)

FULTON

28 Jan 1823
FULTON created from Non-County Area 3 attached to PIKE. Non-County Area 5 attached to FULTON "until otherwise disposed of." (Ill. Laws 1822-1823, pp. 88-89)
13 Jan 1825
FULTON lost to creation of KNOX, PEORIA, and SCHUYLER; Non-County Area 5 attached to FULTON lost to creation of HENRY, KNOX, PEORIA, and PUTNAM. (Ill. Laws 1824-1825, pp. 85-87, 92-96)
28 Feb 1845
FULTON gained part of Non-County Area 5 ("the gore"); Non-County Area 5 eliminated. (Ill. Laws 1844-1845, p. 267)

GALLATIN

14 Sep 1812
GALLATIN created by Illinois Territory from RANDOLPH; boundary with JOHNSON is estimated. (Ill. Terr. Recs., 26; Terr. Papers U.S., 17:643)
11 Dec 1813
GALLATIN exchanged with RANDOLPH. (Ill. Terr. Laws, 120)
28 Nov 1814
GALLATIN lost to creation of EDWARDS. (Ill. Terr. Laws, 128-130)
01 Feb 1816
GALLATIN lost to creation of WHITE; boundary with WHITE is estimated. (Ill. Terr. Laws, 185-186)
01 Apr 1816
GALLATIN lost to creation of POPE. (Ill. Terr. Laws, 217-219)
26 Dec 1816
GALLATIN lost to POPE. (Ill. Terr. Laws, 239)
02 Jan 1818
GALLATIN lost to creation of FRANKLIN. (Ill. Terr. Laws, 290-291)
03 Dec 1818
GALLATIN became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
20 Feb 1847
GALLATIN lost to HARDIN. (Ill. Laws 1846-1847, priv. and spec., pp. 30-31)
02 Aug 1847
GALLATIN lost to creation of SALINE by local referendum. (Ill. Laws 1846-1847, priv. and spec., pp. 34-37)
28 Apr 1851
GALLATIN gained all of SALINE when SALINE was abolished by the state legislature. (History of Gallatin, Saline, 66-67; Ill. Laws 1851, gen., pp. 28-29)
02 Aug 1852
GALLATIN lost to re-creation of SALINE by local referendum. (History of Gallatin, Saline, 66-67; Ill. Laws 1852, pp. 106-108; Ill. Reports, 12:391-397)
07 Nov 1854
GALLATIN lost to WHITE. (History of Gallatin, Saline, 42-43; Ill. Laws 1853, gen., pp. 265-266; Ill. Laws 1854, priv., pp. 143-144)

GREENE

20 Jan 1821
GREENE created from MADISON; part of MADISON became Non-County Area 2 and was attached to GREENE "for all purposes." (Ill. Laws 1820-1821, pp. 26-27)
31 Jan 1823
GREENE lost part of attached Non-County Area 2 to creation of MORGAN. (Ill. Laws 1822-1823, pp. 108-109; Laws 1834-1835, pp. 62-63)
03 Jan 1825
GREEN lost part of attached Non-County Area 2 to MADISON. (Ill. Laws 1824-1825, p. 53)
17 Jan 1829
GREENE lost all of attached Non-County Area 2 to creation of MACOUPIN; Non-County Area 2 eliminated. (Ill. Rev. Code 1828-1829, pp. 26-28)
05 Aug 1839
GREENE lost to creation of JERSEY. (Ill. Laws 1838-1839, pp. 208-211)
04 Mar 1843
Legislature authorized creation of BENTON (proposed) from GREENE, MACOUPIN, and MORGAN, dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 104-108)
03 Mar 1851
GREENE exchanged with JERSEY. (Ill. Laws 1851, gen., pp. 145-146)

GRUNDY

17 Feb 1841
GRUNDY created from LA SALLE. (Ill. Laws 1840-1841, pp. 74-75)

HAMILTON

08 Feb 1821
HAMILTON created from WHITE. (Ill. Laws 1820-1821, pp. 113-114)
07 Nov 1854
HAMILTON gained from SALINE. (History of Gallatin, Saline, 42-43; Ill. Laws 1853, gen., pp. 265-266; Ill. Laws 1854, priv., pp. 143-144)

HANCOCK

13 Jan 1825
HANCOCK created from Non-County Area 3 attached to PIKE; HANCOCK not fully organized, attached to ADAMS "for county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
03 Aug 1829
HANCOCK fully organized, detached from ADAMS. (Scofield, 679)
03 Mar 1837
HANCOCK boundaries were extended to the middle of the Mississippi River [not mapped]. (Ill. Laws 1836-1837, pp. 91-92)

HARDIN

05 Aug 1839
HARDIN created from POPE. (Ill. Laws 1838-1839, pp. 234-236)
08 Jan 1840
HARDIN lost to POPE. (Ill. Laws 1839-1840, spec. sess., pp. 38-40)
20 Feb 1847
HARDIN gained from GALLATIN. (Ill. Laws 1846-1847, priv. and spec., pp. 30-31)

HARRISON (proposed)

14 Feb 1855
Legislature authorized creation of HARRISON (proposed) from CHAMPAIGN, McLEAN, and Non-County Area 4 attached to VERMILION, dependent upon local referendum that failed. (Ill. Laws 1855, pub., pp. 113-117)

HENDERSON

20 Jan 1841
HENDERSON created from WARREN. (Ill. Laws 1840-1841, pp. 67-69)

HENRY

13 Jan 1825
HENRY created from Non-County Area 5 attached to FULTON. (Ill. Laws 1824-1825, pp. 85-87, 92-96)
17 Feb 1827
HENRY lost to creation of JO DAVIESS. (Ill. Rev. Code 1826-1827, pp. 117-118)
15 Jan 1831
HENRY gained from JO DAVIESS and PUTNAM, lost to KNOX; HENRY attached to KNOX "for all judicial and other purposes." (Ill. Laws 1830-1831, pp. 54-57, 62-63)
16 Jan 1836
HENRY lost to creation of WHITESIDE. (Ill. Laws 1835-1836, pp. 273-278)
01 Mar 1837
Legislature authorized creation of COFFEE (proposed) from HENRY, KNOX, and PUTNAM, dependent on local referendum that failed [no change]. (Ill. Laws 1836-1837, pp. 86-88)
04 Mar 1837
Boundary between HENRY and KNOX was clarified [no change]. (Ill. Laws 1836-1837, p. 89)
19 Jun 1837
HENRY fully organized, detached from KNOX. (Ill. Laws 1836-1837, pp. 90-91)
01 Feb 1840
Legislature authorized STARK to gain from HENRY all of township 14 north, range 5 east; and parts of township 14 north, range 4 east, and township 15 north, ranges 4 and 5 east, dependent on local referendum that failed [no change]. (Ill. Laws 1839-1840, spec. sess., pp. 62-63)
12 Feb 1849
Legislature authorized STARK to gain from HENRY a) all of township 14 north, range 5 east, or, b) just the southern half thereof, dependent on local referendum that failed [no change]. (Ill. Laws 1849, 1st sess., gen., pp. 55-56)

HIGHLAND (extinct)

11 Feb 1843
MARQUETTE (later HIGHLAND, extinct) created from ADAMS. (Ill. Laws 1842-1843, pp. 77-83)
27 Feb 1847
MARQUETTE renamed HIGHLAND (extinct); HIGHLAND (extinct) gained from ADAMS. (Ill. Laws 1846-1847, gen., pp. 38-41)
by 31 Dec 1848
HIGHLAND (extinct) lost all territory to ADAMS when it failed to organize as a county; HIGHLAND eliminated. (Wilcox, David F., 1:119-120)

HOLMES (proposed)

31 Jan 1857
Legislature authorized creation of HOLMES (proposed) from CHAMPAIGN, VERMILION, and Non-County Area 4 attached to VERMILION, dependent on local referendum that failed. HOLMES was in the same general area as FORD, which was created 5 April 1859. (Ill. Laws 1857, pub., pp. 93-98)

ILLINOIS (Va., extinct)

09 Dec 1778
ILLINOIS County (Va., extinct) created by Virginia to encompass all territory north and west of the Ohio River and east of the Mississippi River, including all of present Illinois. Virginia claimed this territory on the basis of its 1609 charter. (Hening, 9:552-555, 10:303-304; Robinson, 55)
01 Mar 1784
Virginia ceded to the United States its charter claims to territory "northwestward of the river Ohio"; ILLINOIS County (Va.) eliminated. (Cappon, Petchenik, and Long, 62, 130-131; Hening, 11:571-575)

Illinois Territory

01 Mar 1809
The United States created Illinois Territory from Indiana Territory; included all of present Illinois (except some small areas along the Wabash River), and parts of present Wisconsin, Michigan, and Minnesota. Map depicts non-county area of Illinois Territ (U.S. Stat., vol. 2, ch 13 [1809], sec. 1/pp. 514-515)
28 Apr 1809
Non-county area in Illinois Territory lost to RANDOLPH and ST. CLAIR; eliminated all non-county area in Illinois Territory. (Ill. Terr. Recs., 3-4; Terr. Papers U.S., 17:620-621)

Indiana Territory

04 Jul 1800
The United States created Indiana Territory from the Northwest Territory; included all of present Illinois and Wisconsin, and parts of present Michigan, Minnesota and Ohio; Northwest Territory eliminated. Map depicts non-county area of Indiana Territory i (Terr. Papers U.S., 3:86-88; U.S. Stat., vol. 2, ch. 41 [1800]/pp. 58-59)
03 Feb 1801
Indiana Territory lost all non-county area in present Illinois to ST. CLAIR. (Ind. Terr., Exec. Journal, 97-100; Pence and Armstrong, 212, 520)
30 Jun 1805
Michigan Territory was created from Indiana Territory; eliminating WAYNE (Indiana Terr.). The northeastern corner of present Illinois became non-county area in Indiana Territory. (Terr. Papers U.S., 10:5-7; U.S. Stat., vol. 2, ch. 5 [1805]/pp. 309-310)
01 Mar 1809
The United States created Illinois Territory from Indiana Territory; Indiana Territory eliminated from present Illinois, except for two small areas along the Wabash River. (U.S. Stat., vol. 2, ch 13 [1809], sec. 1/pp. 514-515)

IROQUOIS

26 Feb 1833
IROQUOIS created from Non-County Area 9 and Non-County Area 4 attached to VERMILION; IROQUOIS not fully organized, attached to VERMILION "for judicial and other county purposes." (Ill. Laws 1832-1833, priv., pp. 19-20)
24 Feb 1834
IROQUOIS fully organized, detached from VERMILION. (Beckwith, Iroquois, 343)
12 Jan 1836
IROQUOIS lost to creation of WILL. (Ill. Laws 1835-1836, pp. 262-263)
11 Feb 1851
Legislature authorized creation of KANKAKEE from IROQUOIS and WILL, dependent on local referendum that failed [see 5 April 1853]. (Ill. Laws 1851, gen., pp. 30-35)
05 Apr 1853
IROQUOIS lost to creation of KANKAKEE. (Ill. Laws 1853, gen., pp. 159-163)
08 Mar 1867
Legislature authorized KANKAKEE to gain from IROQUOIS the remainder of township 29 north all along its southern boundary, dependent on local referendum that failed [no change]. (Ill. Laws 1867, priv., 3:632-634)

JACKSON

01 Apr 1816
JACKSON created by Illinois Territory from JOHNSON and RANDOLPH. (Ill. Terr. Laws, 215-217; Ill. Laws 1822-1823, pp. 122-123)
03 Dec 1818
JACKSON became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
29 Jan 1827
JACKSON lost to creation of PERRY. (Ill. Rev. Code 1826-1827, pp. 110-113)

JASPER

15 Feb 1831
JASPER created from CLAY and CRAWFORD; JASPER not fully organized, parts attached to CLAY and CRAWFORD until "organized." (Ill. Laws 1830-1831, pp. 50-52)
19 Dec 1834
JASPER fully organized, detached from CLAY and CRAWFORD. (Ill. Laws 1834-1835, pp. 154-155)

JEFFERSON

26 Mar 1819
JEFFERSON created from EDWARDS and WHITE. (Ill. Laws 1819, pp. 267-268)
29 Mar 1819
JEFFERSON gained from EDWARDS. (Ill. Laws 1819, pp. 320-321)
14 Feb 1821
JEFFERSON lost to creation of FAYETTE. (Ill. Laws 1820-1821, pp. 164-167)
24 Jan 1823
JEFFERSON lost to creation of MARION. (Ill. Laws 1822-1823, pp. 49-50)

JERSEY

05 Aug 1839
JERSEY created from GREENE. (Ill. Laws 1838-1839, pp. 208-211)
03 Mar 1851
JERSEY exchanged with GREENE. (Ill. Laws 1851, gen., pp. 145-146)

JO DAVIESS

17 Feb 1827
JO DAVIESS created from HENRY, MERCER, and PUTNAM. (Ill. Rev. Code 1826-1827, pp. 117-118)
15 Jan 1831
JO DAVIESS lost to HENRY and PUTNAM. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
09 Feb 1831
JO DAVIESS lost to creation of ROCK ISLAND; ROCk ISLAND not fully organized, attached to JO DAVIESS "for all judicial and other county purposes." (Ill. Laws 1830-1831, pp. 52-53)
01 Mar 1833
ROCK ISLAND fully organized, detached from JO DAVIESS. (Ill. Laws 1832-1833, priv., pp. 17-18)
16 Jan 1836
JO DAVIESS lost to creation of OGLE, WHITESIDE, and WINNEBAGO, and lost to Non-County Area 8; WHITESIDE not fully organized, attached to JO DAVIESS until "organized." (Ill. Laws 1835-1836, pp. 273-278)
24 Dec 1836
WHITESIDE detached from JO DAVIESS, attached to OGLE "for all judicial and county purposes." (History of Ogle, 299-300; Ill. Laws 1835-1836, p. 277)
04 Mar 1837
JO DAVIESS lost to creation of STEPHENSON. (Ill. Laws 1836-1837, pp. 96-100)
22 Feb 1839
JO DAVIESS lost to OGLE and lost to creation of CARROLL. (Ill. Laws 1838-1839, pp. 160-162)

JOHNSON

14 Sep 1812
JOHNSON created by Illinois Territory from RANDOLPH; boundary with GALLATIN is estimated. (Ill. Terr. Recs., 26; Terr. Papers U.S., 17:643)
01 Apr 1816
JOHNSON lost to creation of JACKSON and POPE. (Ill. Terr. Laws, 215-219; Ill. Laws 1822-1823, pp. 122-123)
02 Jan 1818
JOHNSON gained from POPE, lost to creation of FRANKLIN and UNION, and lost to creation of Non-County Area 1. (Ill. Terr. Laws, 290-294)
03 Dec 1818
JOHNSON became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
08 Feb 1843
JOHNSON lost to creation of MASSAC. (Ill. Laws 1842-1843, pp. 74-76)

KANE

16 Jan 1836
KANE created from Non-County Area 8 attached to LA SALLE. (Ill. Laws 1835-1836, pp. 273-278)
01 May 1837
KANE lost to creation of DE KALB. (Ill. Laws 1836-1837, pp. 96-100)
19 Feb 1841
KANE lost to creation of KENDALL. (Ill. Laws 1840-1841, pp. 75-77)

KANKAKEE (proposed)

11 Feb 1851
Legislature authorized creation of KANKAKEE (proposed) from IROQUOIS and WILL, dependent on local referendum that failed; second attempt to create KANKAKEE on 5 April 1853, with slightly different boundaries, was successful. (Ill. Laws 1851, gen., pp. 30-35)

KANKAKEE

05 Apr 1853
KANKAKEE created from IROQUOIS and WILL. Boundaries were somewhat different from KANKAKEE (proposed) authorized on 11 February 1851. (Ill. Laws 1853, gen., pp. 159-163)
04 Jun 1855
KANKAKEE gained from Non-County Area 4 attached to VERMILION. (Ill. Laws 1855, priv., pp. 662-663)
08 Mar 1867
Legislature authorized KANKAKEE to gain from IROQUOIS the remainder of township 29 north all along its southern boundary, dependent on local referendum that failed [no change]. (Ill. Laws 1867, priv., 3:632-634)

KENDALL

19 Feb 1841
KENDALL created from KANE and LA SALLE. (Ill. Laws 1840-1841, pp. 75-77)

KNOX (Ind.)

20 Jun 1790
KNOX (Ind.) created by the Northwest Territory from non-county area; included parts of present Illinois, Indiana, Michigan, Ohio, and Wisconsin. (Terr. Papers U.S., 3:313)
15 Aug 1796
KNOX (Ind.) lost to creation of WAYNE (Northwest Territory, extinct); KNOX (Ind.) eliminated from present Michigan and Wisconsin. (Terr. Papers U.S., 2:567-568, 3:447; Chase, 3:ch. 332/p. 2096)
22 Jun 1798
KNOX (Ind.) lost to HAMILTON (Ohio); KNOX's area within present Illinois was unchanged. (Terr. Papers U.S., 3:509)
04 Jul 1800
KNOX (Ind.) became a county in Indiana Territory when Indiana Territory was created from the Northwest Territory. (Terr. Papers U.S., 3:86-88; U.S. Stat., vol. 2, ch. 41 [1800]/pp. 58-59)
03 Feb 1801
KNOX (Ind.) gained non-county area in present Indiana, Michigan, and Ohio; lost to creation of CLARK (Ind.) and lost to RANDOLPH and ST. CLAIR. (Ind. Terr., Exec. Journal, 97-100; Pence and Armstrong, 212, 520)
01 Mar 1803
KNOX (Ind.) lost to creation of WAYNE (Indiana Territory, extinct), lost to HAMILTON (Ohio) and to non-county area in Ohio; KNOX's area within present Illinois was unchanged. (Ind. Terr., Exec. Journal, 114-115; Pence and Armstrong, 218; U.S. Stat., vol. 2, ch. 40 [1802], secs. 1-3/pp. 173-174; Van Zandt, 112)
01 Dec 1808
KNOX (Ind.) lost to creation of HARRISON (Ind.); KNOX's area within present Illinois was unchanged. (Ind. Terr. Laws, 1801-1809, 645-646)
01 Mar 1809
KNOX (Ind.) lost to creation of Illinois Territory. KNOX was effectively eliminated from Illinois, although some small areas of present Illinois along the Wabash River remained part of KNOX until 1816. (U.S. Stat., vol. 2, ch 13 [1809], sec. 1/pp. 514-515)

KNOX

13 Jan 1825
KNOX created from FULTON and Non-County Area 5 attached to FULTON. (Ill. Laws 1824-1825, pp. 85-87, 92-96)
15 Jan 1831
KNOX gained from HENRY and PUTNAM. HENRY attached to KNOX "for all judicial and other purposes." (Ill. Laws 1830-1831, pp. 54-57, 62-63)
01 Mar 1837
Legislature authorized creation of COFFEE (proposed) from KNOX, HENRY, and PUTNAM, dependent on local referendum that failed [no change]. (Ill. Laws 1836-1837, pp. 86-88)
04 Mar 1837
Boundary between KNOX and HENRY was clarified [no change]. (Ill. Laws 1836-1837, p. 89)
19 Jun 1837
HENRY fully organized, detached from KNOX. (Ill. Laws 1836-1837, pp. 90-91)
18 Mar 1839
KNOX lost to STARK. (Ill. Laws 1838-1839, pp. 229-230)

LA SALLE

15 Jan 1831
LA SALLE created from PUTNAM, Non-County Area 4 attached to VERMILION, and Non-County Area 6 attached to TAZEWELL. Part of PUTNAM became Non-County Area 8 and was attached to LA SALLE for administrative and judicial purposes. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
16 Jan 1836
LA SALLE lost most of attached Non-County Area 8 to creation of KANE, McHENRY, OGLE, and WINNEBAGO. Non-County Area 8 effectively detached from LA SALLE. (Ill. Laws 1835-1836, pp. 273-278)
27 Feb 1837
LA SALLE lost to creation of LIVINGSTON. (Ill. Laws 1836-1837, pp. 83-85)
02 Mar 1839
Legislature authorized MARSHALL and PUTNAM to gain from LA SALLE townships 29 to 32, and township 33 south of the Big Vermilion River, range 1 east, dependent on local referendum that failed [no change]. (Ill. Laws 1838-1839, p. 241)
17 Feb 1841
LA SALLE lost to creation of GRUNDY. (Ill. Laws 1840-1841, pp. 74-75)
19 Feb 1841
LA SALLE lost to creation of KENDALL. (Ill. Laws 1840-1841, pp. 75-77)
12 Apr 1843
LA SALLE lost to MARSHALL. (Ill. Laws 1842-1843, pp. 93-94)
15 Feb 1851
Legislature authorized PUTNAM to gain from LA SALLE townships 31 and 32 north, range 1 east, dependent on local referendum that failed [no change]. (Ill. Laws 1851, gen., pp. 111-112)

LAKE

01 Mar 1839
LAKE created from McHENRY. (Ill. Laws 1838-1839, pp. 216-217)

LAWRENCE

16 Jan 1821
LAWRENCE created from CRAWFORD and EDWARDS. (Ill. Laws 1820-1821, pp. 16-17)
23 Dec 1824
LAWRENCE lost to creation of CLAY. (Ill. Laws 1824-1825, pp. 18-20)
07 Jun 1841
LAWRENCE lost to creation of RICHLAND. (Ill. Laws 1840-1841, pp. 77-79)

LEE

27 Feb 1839
LEE created from OGLE. (Ill. Laws 1838-1839, pp. 170-172)

LINCOLN (proposed)

09 Jul 1867
Legislature authorized creation of LINCOLN (proposed) from CHAMPAIGN and VERMILION, dependent on local referendum that failed. (Ill. Laws 1867, priv., 1:868-873)

LIVINGSTON

27 Feb 1837
LIVINGSTON created from LA SALLE, McLEAN, and Non-County Area 4 attached to VERMILION. (Ill. Laws 1836-1837, pp. 83-85)

LOGAN

15 Feb 1839
LOGAN created from SANGAMON. (Ill. Laws 1838-1839, pp. 104-107)
27 Jan 1840
LOGAN gained from TAZEWELL. (Ill. Laws 1839-1840, spec. sess., p. 29)
26 Feb 1845
LOGAN gained from DE WITT. (Ill. Laws 1844-1845, p. 189)

MACON

19 Jan 1829
MACON created from all of Non-County Area 7 attached to SHELBY. (Ill. Rev. Code 1828-1829, pp. 28-31)
01 Mar 1839
MACON lost to creation of DE WITT. (Ill. Laws 1838-1839, pp. 199-201)
02 Mar 1839
MACON gained from SANGAMON. (Ill. Laws 1838-1839, p. 265)
27 Jan 1841
MACON lost to creation of PIATT. (Ill. Laws 1840-1841, pp. 71-74)
24 Feb 1841
Legislature authorized creation of OKAW (proposed) from MACON and SHELBY, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, pp. 80-83)
16 Feb 1843
MACON lost to creation of MOULTRIE. (Ill. Laws 1842-1843, pp. 83-85)

MACOUPIN

17 Jan 1829
MACOUPIN created from MADISON and all of Non-County Area 2 attached to GREENE. (Ill. Rev. Code 1828-1829, pp. 26-28)
27 Feb 1841
Legislature authorized creation of ALLEN (proposed) from MACOUPIN, MORGAN, and SANGAMON, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, pp. 87-90)
04 Mar 1843
Legislature authorized creation of BENTON (proposed) from MACOUPIN, GREENE, and MORGAN, dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 104-108)
15 Feb 1851
Legislature authorized creation of OREGON (proposed) from MACOUPIN, MORGAN, and SANGAMON, dependent on local referendum that failed [no change]. (Ill. Laws 1851, gen., pp. 131-134)

MADISON

14 Sep 1812
MADISON created by Illinois Territory from RANDOLPH and ST. CLAIR; MADISON included territory in present Illinois, Wisconsin, Michigan, Minnesota, and a small area of Indiana. (Ill. Terr. Recs., 26; Terr. Papers U.S., 17:643)
28 Nov 1814
MADISON lost to creation of EDWARDS; MADISON eliminated from present Indiana. (Ill. Terr. Laws, 128-130)
04 Jan 1817
MADISON lost to creation of BOND. (Ill. Terr. Laws, 254-256)
06 Jan 1818
Boundary between MADISON and ST. CLAIR was redefined [no change]. (Ill. Terr. Laws, 311)
03 Dec 1818
MADISON lost all territory in present Michigan, Minnesota, and Wisconsin to Michigan Territory when the state of Illinois was created from Illinois Territory; MADISON became a county in the state of Illinois. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
20 Jan 1821
MADISON lost to creation of GREENE and to creation of Non-County Area 2. (Ill. Laws 1820-1821, pp. 26-27)
30 Jan 1821
MADISON lost to creation of SANGAMON. (Ill. Laws 1820-1821, pp. 45-46)
31 Jan 1821
MADISON lost to creation of PIKE. (Ill. Laws 1820-1821, p. 59)
12 Feb 1821
MADISON lost to creation of MONTGOMERY. (Ill. Laws 1820-1821, pp. 142-143)
03 Jan 1825
MADISON gained from Non-County Area 2 attached to GREENE. (Ill. Laws 1824-1825, p. 53)
17 Jan 1829
MADISON lost to creation of MACOUPIN. (Ill. Rev. Code 1828-1829, pp. 26-28)
19 Feb 1841
Legislature authorized BOND to gain from MADISON the eastern halves of townships 4 to 6 north, range 5 west, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, p. 80)
02 Mar 1843
MADISON lost to BOND. (Ill. Laws 1842-1843, pp. 98-99)

MARION

24 Jan 1823
MARION created from FAYETTE and JEFFERSON. (Ill. Laws 1822-1823, pp. 49-50)

MARQUETTE (see HIGHLAND)

MARSHALL

19 Jan 1839
MARSHALL created from PUTNAM. (Ill. Laws 1838-1839, pp. 43-45)
02 Mar 1839
Legislature authorized MARSHALL to gain townships 29 and 30 north, range 1 east, from LA SALLE, dependent on local referendum that failed [no change]. (Ill. Laws 1838-1839, p. 241)
12 Apr 1843
MARSHALL gained from LA SALLE. (Ill. Laws 1842-1843, pp. 93-94)

MASON

20 Jan 1841
MASON created from MENARD and TAZEWELL. (Ill. Laws 1840-1841, pp. 69-71)

MASSAC

08 Feb 1843
MASSAC created from JOHNSON and POPE. (Ill. Laws 1842-1843, pp. 74-76)
03 Mar 1843
MASSAC lost to POPE. (Ill. Laws 1842-1843, p. 101)
05 Jun 1843
MASSAC lost to creation of PULASKI. (Ill. Laws 1842-1843, pp. 99-101)

McDONOUGH

25 Jan 1826
McDONOUGH created from Non-County Area 3 attached to SCHUYLER; McDONOUGH not fully organized, attached to SCHUYLER "for county purposes." (Ill. Laws 1826, pp. 76-77)
03 Jul 1830
McDONOUGH fully organized, detached from SCHUYLER. (McLean, 624)

McHENRY

16 Jan 1836
McHENRY created from COOK and Non-County Area 8 attached to LA SALLE; McHENRY not fully organized, attached to COOK until "organized". (Ill. Laws 1835-1836, pp. 273-278)
01 Mar 1837
McHENRY fully organized, detached from COOK; McHENRY's boundaries were extended to the Illinois state limits in Lake Michigan [not mapped]. (Ill. Laws 1836-1837, pp. 89-90)
01 Mar 1839
McHENRY lost to creation of LAKE. (Ill. Laws 1838-1839, pp. 216-217)
02 Mar 1839
Legislature authorized BOONE to gain townships 43 to 46, range 5 east, fromf McHENRY, dependent on local referendum that failed [no change]. (Ill. Laws 1838-1839, p. 242)
24 Feb 1843
McHENRY boundaries were redefined [no change]. (Ill. Laws 1842-1843, p. 91)

McLEAN

25 Dec 1830
McLEAN created from TAZEWELL and Non-County Area 6 attached to TAZEWELL. (Ill. Laws 1830-1831, pp. 57-59)
27 Feb 1837
McLEAN lost to creation of LIVINGSTON. (Ill. Laws 1836-1837, pp. 83-85)
01 Mar 1839
McLEAN lost to creation of DE WITT. (Ill. Laws 1838-1839, pp. 199-201)
27 Feb 1841
McLEAN lost to creation of WOODFORD. (Ill. Laws 1840-1841, pp. 84-86)
28 Feb 1843
McLEAN exchanged with WOODFORD. (Ill. Laws 1842-1843, p. 91)
14 Feb 1855
Legislature authorized creation of HARRISON (proposed) from McLEAN, CHAMPAIGN, and Non-County Area 4 attached to VERMILION, dependent on local referendum that failed [no change]. (Ill. Laws 1855, pub., pp. 113-117)

MENARD

15 Feb 1839
MENARD created from SANGAMON. (Ill. Laws 1838-1839, pp. 104-107)
20 Jan 1841
MENARD lost to creation of MASON. (Ill. Laws 1840-1841, pp. 69-71)
02 Mar 1843
MENARD gained from SANGAMON. (Ill. Laws 1842-1843, p. 94)
28 Feb 1847
MENARD gained from SANGAMON. (Ill. Laws 1846-1847, priv. and spec., p. 39)

MERCER

13 Jan 1825
MERCER created from Non-County Area 3 attached to PIKE; MERCER was divided into two parts. MERCER not fully organized, attached to SCHUYLER "for all county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
01 Mar 1826
MERCER detached from SCHUYLER, attached to PEORIA "for county purposes." (Ill. Laws 1826, pp. 76-77)
17 Feb 1827
MERCER lost to creation of JO DAVIESS. (Ill. Rev. Code 1826-1827, pp. 117-118)
27 Jan 1831
MERCER detached from PEORIA, attached to WARREN "for judicial and other purposes." (Ill. Laws 1830-1831, pp. 67-68)
31 Jan 1835
MERCER fully organized, detached from WARREN. (Ill. Laws 1835-1835, p. 156)
03 Mar 1837
MERCER boundaries were extended to the middle of the Mississippi River [not mapped]. (Ill. Laws 1836-1837, pp. 91-92)
08 Feb 1849
Legislature authorized ROCK ISLAND to gain from MERCER township 15 north, ranges 1 and 2 west, dependent on local referendum that failed [no change]. (Ill. Laws 1849, 1st sess., gen., pp. 51-52)

MICHIGAN (proposed)

02 Mar 1837
Legislature authorized creation of MICHIGAN (proposed) from COOK, dependent on local referendum that failed. MICHIGAN was in the same general area as DU PAGE, created 9 February 1839. (Ill. Laws 1836-1837, pp. 82-83)

MILTON (proposed)

21 Feb 1843
Legislature authorized creation of MILTON (proposed) from VERMILION, dependent on local referendum that failed. (Ill. Laws 1842-1843, pp. 88-91)

MONROE

01 Jun 1816
MONROE created by Illinois Territory from RANDOLPH and ST. CLAIR. (Ill. Terr. Laws, 195-198)
03 Dec 1818
MONROE became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
15 Jan 1825
MONROE gained from ST. CLAIR. (Ill. Laws 1824-1825, pp. 109-110)
09 Jan 1827
MONROE gained from ST. CLAIR. (Ill. Laws 1826-1827, pp. 7-8)
20 Jan 1829
Boundary between MONROE and RANDOLPH was clarified [no change]. (Ill. Rev. Code 1828-1829, pp. 31-32)

MONTGOMERY

12 Feb 1821
MONTGOMERY created from BOND and MADISON. (Ill. Laws 1820-1821, pp. 142-143)
23 Jan 1827
MONTGOMERY gained from FAYETTE. (Ill. Rev. Code 1826-1827, pp. 115-117)
15 Feb 1839
MONTGOMERY lost to creation of DANE (now CHRISTIAN). (Ill. Laws 1838-1839, pp. 104-107)
06 Feb 1843
Legislature authorized creation of AUDUBON (proposed) from MONTGOMERY, FAYETTE, and SHELBY, dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 73-74)

MORGAN

31 Jan 1823
MORGAN created from SANGAMON and Non-County Area 2 attached to GREENE. (Ill. Laws 1822-1823, pp. 108-109; Ill. Laws 1834-1835, pp. 62-63)
17 Apr 1837
MORGAN lost to creation of CASS. (Ill. Laws 1836-1837, pp. 101-103; Ill. Laws 1837, spec. sess., pp. 48-50)
16 Feb 1839
MORGAN lost to creation of SCOTT. (Ill. Laws 1838-1839, pp. 126-130)
27 Feb 1841
Legislature authorized creation of ALLEN (proposed) from MORGAN, MACOUPIN, and SANGAMON, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, pp. 87-90)
04 Mar 1843
Legislature authorized CASS to gain from MORGAN the southern half of township 17 north all along its southern border, dependent on local referendum that failed [see 5 May 1845; no change]. Legislature authorized creation of BENTON (proposed) from MORGAN, (Ill. Laws 1842-1843, pp. 104-108)
05 May 1845
MORGAN lost to CASS. (Ill. Laws 1844-1845, pp. 313-315)
15 Feb 1851
Legislature authorized creation of OREGON (proposed) from MORGAN, MACOUPIN, and SANGAMON, dependent on local referendum that failed [no change]. (Ill. Laws 1851, gen., pp. 131-134)

MOULTRIE

16 Feb 1843
MOULTRIE created from MACON and SHELBY. On 24 February 1841, an unsuccessful attempt was made to create OKAW (proposed) in the same general area. (Ill. Laws 1842-1843, pp. 83-85)

Non-County Area 1

02 Jan 1818
Non-County Area 1 created from JOHNSON; attached to UNION for administrative and judicial purposes. (Ill. Terr. Laws, 292-294)
04 Mar 1819
Non-County Area 1 attached to UNION lost all territory to creation of ALEXANDER; Non-County Area 1 eliminated. (Ill. Laws 1819, pp. 113-114)

Non-County Area 2

20 Jan 1821
Non-County Area 2 created from MADISON; Non-County Area 2 was attached to GREENE "for all purposes." (Ill. Laws 1820-1821, pp. 26-27)
31 Jan 1823
Non-County Area 2 attached to GREENE lost to creation of MORGAN. (Ill. Laws 1822-1823, pp. 108-109; Laws 1834-1835, pp. 62-63)
03 Jan 1825
Non-County Area 2 attached to GREENE lost to MADISON. (Ill. Laws 1824-1825, p. 53)
17 Jan 1829
Non-County Area 2 attached to GREENE lost all territory to creation of MACOUPIN; Non-County Area 2 eliminated. (Ill. Rev. Code 1828-1829, pp. 26-28)

Non-County Area 3

30 Dec 1822
Non-County Area 3 created from PIKE; Non-County Area 3 attached to PIKE "until otherwise disposed of." (Ill. Laws 1822-1823, pp. 84-85)
03 Jan 1823
Non-County Area 3 attached to PIKE lost to creation of Non-County Area 4. (History of Edgar, 514-515; Ill. Laws 1822-1823, pp. 74-75)
28 Jan 1823
Non-County Area 3 attached to PIKE lost to creation of FULTON and to creation of Non-County Area 5. (Ill. Laws 1822-1823, pp. 88-89)
13 Jan 1825
Non-County Area 3 attached to PIKE lost to creation of ADAMS, HANCOCK, MERCER, SCHUYLER, and WARREN. Non-County Area 3 detached from PIKE, attached to SCHUYLER "for all county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
25 Jan 1826
Non-County Area 3 attached to SCHUYLER lost all territory to creation of McDONOUGH; Non-County Area 3 eliminated. (Ill. Laws 1826, pp. 76-77)

Non-County Area 4

03 Jan 1823
Non-County Area 4 created from CLARK and part of Non-County Area 3 attached to PIKE; Non-County Area 4 attached to EDGAR for administrative and judicial purposes. (History of Edgar, 514-515; Ill. Laws 1822-1823, pp. 74-75)
13 Jan 1825
Non-County Area 4 attached to EDGAR lost to creation of PUTNAM. (Ill. Laws 1824-1825, pp. 85-87, 92-96)
18 Jan 1826
Non-County Area 4 attached to EDGAR lost to creation of VERMILION, gained from CLARK; Non-County Area 4 detached from EDGAR, attached to VERMILION "for all county purposes." (Ill. Laws 1826, pp. 50-53)
15 Jan 1831
Non-County Area 4 attached to VERMILION lost to creation of LA SALLE. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
20 Feb 1833
Non-County Area 4 attached to VERMILION lost to creation of CHAMPAIGN. (Ill. Laws 1832-1833, priv., pp. 28-30)
26 Feb 1833
Non-County Area 4 attached to VERMILION lost to VERMILION and lost to creation of IROQUOIS. (Ill. Laws 1832-1833, priv., pp. 19-20)
12 Jan 1836
Non-County Area 4 attached to VERMILION lost to creation of WILL. (Ill. Laws 1835-1836, pp. 262-263)
27 Feb 1837
Non-County Area 4 attached to VERMILION lost to creation of LIVINGSTON. (Ill. Laws 1836-1837, pp. 83-85)
14 Feb 1855
Legislature authorized creation of HARRISON (proposed) from Non-County Area 4 attached to VERMILION, CHAMPAIGN, and McLEAN, dependent on local referendum that failed [no change]. (Ill. Laws 1855, pub., pp. 113-117)
04 Jun 1855
Non-County Area 4 attached to VERMILION lost to KANKAKEE. (Ill. Laws 1855, priv., pp. 662-663)
05 Apr 1859
Non-County Area 4 attached to VERMILION lost all territory to creation of FORD; Non-County Area 4 eliminated. (Ill. Laws 1859, pub., pp. 29-33)

Non-County Area 5

28 Jan 1823
Non-County Area 5 created from Non-County Area 3 attached to PIKE; Non-County Area 5 attached to FULTON "until otherwise disposed of." (Ill. Laws 1822-1823, pp. 88-89)
13 Jan 1825
Non-County Area 5 attached to FULTON lost to creation of HENRY, KNOX, PEORIA, and PUTNAM. A tiny remnant of Non-County Area 5 was unintentionally left as a gore between FULTON and PEORIA until 28 February 1845. (Ill. Laws 1824-1825, pp. 85-87, 92-96)
28 Feb 1845
Non-County Area 5 ("the gore") lost all territory to PEORIA and FULTON; Non-County Area 5 eliminated. (Ill. Laws 1844-1845, p. 267)

Non-County Area 6

23 Dec 1824
Non-County Area 6 created from SANGAMON. (Ill. Laws 1824-1825, pp. 20-22)
13 Jan 1825
Non-County Area 6 attached to PEORIA "for county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
31 Jan 1827
Non-County Area 6 attached to PEORIA lost to creation of TAZEWELL, gained part of Non-County Area 7 attached to SHELBY; Non-County Area 6 detached from PEORIA, attached to TAZEWELL for administrative and judicial purposes. (Ill. Rev. Code 1826-1827, 113-115; Rev. Code 1828-1829, p. 32)
25 Dec 1830
Non-County Area 6 attached to TAZEWELL lost to creation of McLEAN. (Ill. Laws 1830-1831, pp. 57-59)
15 Jan 1831
Non-County Area 6 attached to TAZEWELL lost to PUTNAM and lost to creation of LA SALLE; Non-County Area 6 eliminated. (Ill. Laws 1830-1831, pp. 54-57, 62-63)

Non-County Area 7

23 Jan 1827
Part of FAYETTE reverted to Non-County Area 7 and was attached to SHELBY, "until otherwise provided by law." (Ill. Rev. Code 1826-1827, pp. 115-117)
31 Jan 1827
Non-County Area 7 attached to SHELBY lost to creation of TAZEWELL and lost to Non-County Area 6. (Ill. Rev. Code 1826-1827, 113-115; Rev. Code 1828-1829, p. 32)
19 Jan 1829
Non-County Area 7 attached to SHELBY lost all territory to creation of MACON; Non-County Area 7 eliminated. (Ill. Rev. Code 1828-1829, pp. 28-31)

Non-County Area 8

15 Jan 1831
Non-County Area 8 created from part of PUTNAM; Non-County Area 8 attached to LA SALLE for administrative and judicial purposes. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
16 Jan 1836
Non-County Area 8 gained small area from JO DAVIESS; lost to creation of KANE, McHENRY, OGLE, and WINNEBAGO. Non-County Area 8 effectively detached from LA SALLE. (Ill. Laws 1835-1836, pp. 273-278)
19 Jan 1839
Non-County Area 8 (remnant of JO DAVIESS and non-county area previously attached to LA SALLE) lost all territory to BUREAU; Non-County Area 8 eliminated. (Ill. Laws 1838-1839, pp. 43-45)

Non-County Area 9

15 Jan 1831
Non-County Area 9 created from part of PUTNAM. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
26 Feb 1833
Non-County Area 9 lost to creation of IROQUOIS. (Ill. Laws 1832-1833, priv., pp. 19-20)
12 Jan 1836
Non-County Area 9 lost all territory to creation of WILL; Non-County Area 9 eliminated. (Ill. Laws 1835-1836, pp. 262-263)

Northwest Territory

13 Jul 1787
The United States created the Territory of the United States Northwest of the River Ohio (Northwest Territory), including all of present Illinois, to govern all territory west of Pennsylvania, north of the Ohio River, and east of the Mississippi River to (Terr. Papers U.S., 2:39-50)
27 Apr 1790
Non-county area in the Northwest Territory lost to creation of ST. CLAIR. Map depicts non-county area in the Northwest Territory located in present Illinois. (Terr. Papers U.S., 3:301-303)
20 Jun 1790
Non-county area in the Northwest Territory lost to creation of KNOX (Ind.). Map depicts non-county area in the Northwest Territory located in present Illinois. (Terr. Papers U.S., 3:313)
15 Aug 1796
Non-county area in the Northwest Territory lost to creation of WAYNE (Northwest Territory, extinct). Map depicts non-county area in the Northwest Territory located in present Illinois. (Terr. Papers U.S., 2:567-568, 3:447)
04 Jul 1800
The United States created Indiana Territory from the Northwest Territory; Northwest Territory eliminated. (Terr. Papers U.S., 3:86-88; U.S. Stat., vol. 2, ch. 41 [1800]/pp. 58-59)

OGLE

16 Jan 1836
OGLE created from JO DAVIESS and Non-County Area 8 attached to LA SALLE. (Ill. Laws 1835-1836, pp. 273-278)
24 Dec 1836
WHITESIDE detached from JO DAVIESS, attached to OGLE "for all judicial and county purposes." (History of Ogle, 299-300; Ill. Laws 1835-1836, p. 277)
21 Feb 1839
WHITESIDE fully organized, detached from OGLE. (Ill. Laws 1838-1839, pp. 143-144)
22 Feb 1839
OGLE gained from JO DAVIESS. (Ill. Laws 1838-1839, pp. 160-162)
27 Feb 1839
OGLE lost to creation of LEE. (Ill. Laws 1838-1839, pp. 170-172)
27 Feb 1841
Legislature authorized CARROLL to gain from OGLE the eastern halves of townships 23 to 25 north, range 7 east, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, p. 90)

OKAW (proposed)

24 Feb 1841
Legislature authorized creation of OKAW (proposed) from MACON and SHELBY, dependent on local referendum that failed. OKAW was in the same general area as MOULTRIE, created 16 February 1843. (Ill. Laws 1840-1841, pp. 80-83)

OREGON (proposed)

15 Feb 1851
Legislature authorized creation of OREGON (proposed) from MACOUPIN, MORGAN, and SANGAMON, dependent on local referendum that failed. Previous attempts to create counties in the same general area (ALLEN in 1841 and BENTON in 1843) were also unsuccessful. (Ill. Laws 1851, gen., pp. 131-134)

PEORIA

13 Jan 1825
PEORIA created from FULTON and Non-County Area 5 attached to FULTON. Non-County Area 6 attached to PEORIA "for county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
01 Mar 1826
MERCER and WARREN detached from SCHUYLER, attached to PEORIA "for county purposes." (Ill. Laws 1826, pp. 76-77)
31 Jan 1827
Non-County Area 6 attached to PEORIA lost to creation of TAZEWELL; remaining part of Non-County Area 6 was detached from PEORIA, attached to TAZEWELL for administrative and judicial purposes. (Ill. Rev. Code 1826-1827, pp. 113-115; Rev. Code 1828-1829, p. 32)
27 Jan 1831
WARREN fully organized, detached from PEORIA. MERCER detached from PEORIA, attached to WARREN "for all judicial and other purposes." (Ill. Laws 1830-1831, pp. 67-68)
28 Feb 1845
PEORIA gained part of Non-County Area 5 ("the gore"); Non-County Area 5 eliminated. (Ill. Laws 1844-1845, p. 267)

PERRY

29 Jan 1827
PERRY created from JACKSON and RANDOLPH. (Ill. Rev. Code 1826-1827, pp. 110-113)
01 Mar 1835
PERRY exchanged with FRANKLIN. (Ill. Laws 1834-1835, pp. 36-37)

PIATT

27 Jan 1841
PIATT created from DE WITT and MACON. (Ill. Laws 1840-1841, pp. 71-74)

PIKE

31 Jan 1821
PIKE created from BOND, CLARK, and MADISON. (Ill. Laws 1820-1821, p. 59)
30 Dec 1822
Part of PIKE became Non-County Area 3; Non-County Area 3 was attached to PIKE "until otherwise disposed of." (Ill. Laws 1822-1823, pp. 84-85)
03 Jan 1823
PIKE lost part of attached Non-County Area 3 to creation of Non-County Area 4. (History of Edgar, 514-515; Ill. Laws 1822-1823, pp. 74-75)
28 Jan 1823
PIKE lost part of attached Non-County Area 3 to creation of FULTON and to creation of Non-County Area 5. (Ill. Laws 1822-1823, pp. 88-89)
10 Jan 1825
PIKE lost to creation of CALHOUN. (Ill. Laws 1824-1825, pp. 65-67)
13 Jan 1825
PIKE lost to creation of ADAMS and SCHUYLER. Part of attached Non-County Area 3 lost to creation of ADAMS, HANCOCK, MERCER, SCHUYLER, and WARREN; remainder of Non-County Area 3 detached from PIKE, attached to SCHUYLER "for all county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)

POPE

01 Apr 1816
POPE created by Illinois Territory from GALLATIN and JOHNSON. (Ill. Terr. Laws, 217-219)
26 Dec 1816
POPE gained from GALLATIN. (Ill. Terr. Laws, 239)
02 Jan 1818
POPE lost to JOHNSON. (Ill. Terr. Laws, 292-294)
03 Dec 1818
POPE became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
05 Aug 1839
POPE lost to creation of HARDIN. (Ill. Laws 1838-1839, pp. 234-236)
08 Jan 1840
POPE gained from HARDIN. (Ill. Laws 1839-1840, spec. sess., pp. 38-40)
08 Feb 1843
POPE lost to creation of MASSAC. (Ill. Laws 1842-1843, pp. 74-76)
03 Mar 1843
POPE gained from MASSAC. (Ill. Laws 1842-1843, p. 101)

PULASKI

05 Jun 1843
PULASKI created from ALEXANDER and MASSAC. (Ill. Laws 1842-1843, pp. 99-101)

PUTNAM

13 Jan 1825
PUTNAM created from Non-County Area 4 attached to EDGAR and Non-County Area 5 attached to FULTON. (Ill. Laws 1824-1825, pp. 85-87, 92-96)
17 Feb 1827
PUTNAM lost to creation of JO DAVIESS. (Ill. Rev. Code 1826-1827, pp. 117-118)
15 Jan 1831
PUTNAM gained from JO DAVIESS and Non-County Area 6 attached to TAZEWELL; lost to creation of COOK, LA SALLE, and Non-County Areas 8 and 9; and lost to HENRY and KNOX. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
01 Mar 1837
Legislature authorized creation of COFFEE (proposed) from PUTNAM, HENRY, and KNOX, dependent on local referendum that failed [no change]. (Ill. Laws 1836-1837, pp. 86-88)
03 Apr 1837
PUTNAM lost to creation of BUREAU. (Ill. Laws 1836-1837, pp. 93-95)
19 Jan 1839
PUTNAM lost to creation of MARSHALL. (Ill. Laws 1838-1839, pp. 43-45)
02 Mar 1839
PUTNAM lost to BUREAU and lost to creation of STARK. Legislature authorized PUTNAM to gain townships 31, 32 and 33 south of the Big Vermilion River, range 1 east, from LA SALLE, dependent on local referendum that failed [no change]. (Ill. Laws 1838-1839, pp. 229-232, 241)
15 Feb 1851
Legislature authorized PUTNAM to gain from LA SALLE townships 31 and 32 north, range 1 east, dependent on local referendum that failed [no change]. (Ill. Laws 1851, gen., pp. 111-112)

RANDOLPH

05 Oct 1795
RANDOLPH created by the Northwest Territory from ST. CLAIR. (Terr. Papers U.S., 3:441)
04 Jul 1800
RANDOLPH became a county in Indiana Territory when Indiana Territory was created from the Northwest Territory. (Terr. Papers U.S., 3:86-88; U.S. Stat., vol. 2, ch. 41 [1800]/pp. 58-59)
03 Feb 1801
RANDOLPH gained from KNOX (Ind.) and ST. CLAIR. (Ind. Terr., Exec. Journal, 97-100; Pence and Armstrong, 212, 520)
01 May 1803
RANDOLPH exchanged with ST. CLAIR. (Ind. Terr., Exec. Journal, 117-118)
01 Mar 1809
RANDOLPH became a part of Illinois Territory when Illinois Territory was created from Indiana Territory; RANDOLPH continued de facto, with no new boundaries specified [see 28 April 1809]. (U.S. Stat., vol. 2, ch 13 [1809], sec. 1/pp. 514-515)
28 Apr 1809
RANDOLPH created by Illinois Territory, effectively continuing the county of the same name created by the Northwest Territory in 1795. RANDOLPH gained from ST. CLAIR and gained the former area of KNOX (Ind.) that became part of Illinois Territory; RANDOLP (Ill. Terr. Recs., 3-4; Terr. Papers U.S., 17:620-621)
14 Sep 1812
RANDOLPH lost to creation of GALLATIN, JOHNSON, and MADISON; RANDOLPH eliminated from present Indiana. (Ill. Terr. Recs., 26; Terr. Papers U.S., 17:643)
11 Dec 1813
RANDOLPH exchanged with GALLATIN and ST. CLAIR. (Ill. Terr. Laws, 120-121)
01 Apr 1816
RANDOLPH lost to creation of JACKSON. (Ill. Terr. Laws, 215-217; Ill. Laws 1822-1823, 122-123)
01 Jun 1816
RANDOLPH lost to creation of MONROE. (Ill. Terr. Laws, 195-198)
03 Dec 1818
RANDOLPH became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
29 Jan 1827
RANDOLPH lost to creation of PERRY. (Ill. Rev. Code 1826-1827, pp. 110-113)
20 Jan 1829
Boundary between RANDOLPH and MONROE was clarified [no change]. (Ill. Rev. Code 1828-1829, pp. 31-32)

RICHLAND

07 Jun 1841
RICHLAND created from CLAY and LAWRENCE. (Ill. Laws 1840-1841, pp. 77-79)

ROCK ISLAND

09 Feb 1831
ROCK ISLAND created from JO DAVIESS; ROCK ISLAND not fully organized, attached to JO DAVIESS "for all judicial and other county purposes." (Ill. Laws 1830-1831, pp. 52-53)
01 Mar 1833
ROCK ISLAND fully organized, detached from JO DAVIESS. (Ill. Laws 1832-1833, priv., pp. 17-18)
08 Feb 1849
Legislature authorized ROCK ISLAND to gain from MERCER township 15 north, ranges 1 and 2 west, dependent on local referendum that failed [no change]. (Ill. Laws 1849, 1st sess., gen., pp. 51-52)
04 Mar 1854
ROCK ISLAND exchanged with WHITESIDE. (Ill. Laws 1853, priv., p. 462; Ill. Laws 1854, priv., pp. 161-162)
29 Mar 1869
ROCK ISLAND exchanged with WHITESIDE (repealed act of 4 March 1854). (Ill. Laws 1869, pub., pp. 94-95, 161)

ST. CLAIR

27 Apr 1790
ST. CLAIR created by the Northwest Territory from non-county area. (Terr. Papers U.S., 3:301-303)
05 Oct 1795
ST. CLAIR lost to creation of RANDOLPH. (Terr. Papers U.S., 3:441)
04 Jul 1800
ST. CLAIR became a county in Indiana Territory when Indiana Territory was created from the Northwest Territory. (Terr. Papers U.S., 3:86-88; U.S. Stat., vol. 2, ch. 41 [1800]/pp. 58-59)
03 Feb 1801
ST. CLAIR gained from KNOX (Ind.) and non-county area in present Illinois, Indiana, Michigan, Minnesota, and Wisconsin; ST. CLAIR lost to RANDOLPH. (Ind. Terr., Exec. Journal, 97-100; Pence and Armstrong, 212, 520)
01 Mar 1803
ST. CLAIR lost to creation of WAYNE (Indiana Territory, extinct). (Ind. Terr., Exec. Journal, 114-115; Pence and Armstrong, 218; U.S. Stat., vol. 2, ch. 40 [1802], secs. 1-3/pp. 173-174; Van Zandt, 112)
01 May 1803
ST. CLAIR exchanged with RANDOLPH. (Ind. Terr., Exec. Journal, 117-118)
01 Mar 1809
ST. CLAIR became part of Illinois Territory when Illinois Territory was created from Indiana Territory; ST. CLAIR continued de facto, with no new boundaries specified [see 28 April 1809]. (U.S. Stat., vol. 2, ch 13 [1809], sec. 1/pp. 514-515)
28 Apr 1809
ST. CLAIR created by Illinois Territory, effectively continuing the county of the same name created by the Northwest Territory in 1790. ST. CLAIR exchanged with Indiana Territory, and lost to RANDOLPH; ST. CLAIR eliminated from present Indiana. (Ill. Terr. Recs., 3-4; Terr. Papers U.S., 17:620-621)
14 Sep 1812
ST. CLAIR lost to creation of MADISON; ST. CLAIR eliminated from present Michigan, Minnesota, and Wisconsin. (Ill. Terr. Recs., 26; Terr. Papers U.S., 17:643)
11 Dec 1813
ST. CLAIR exchanged with RANDOLPH. (Ill. Terr. Laws, 120-121)
01 Jun 1816
ST. CLAIR lost to creation of MONROE. (Ill. Terr. Laws, 195-198)
02 Jan 1818
ST. CLAIR lost to creation of WASHINGTON. (Ill. Terr. Laws, 312-314)
06 Jan 1818
Boundary between ST. CLAIR and MADISON was redefined [no change]. (Ill. Terr. Laws, 311)
03 Dec 1818
ST. CLAIR became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
15 Jan 1825
ST. CLAIR lost to MONROE. (Ill. Laws 1824-1825, pp. 109-110)
09 Jan 1827
ST. CLAIR lost to MONROE. (Ill. Laws 1826-1827, pp. 7-8)

SALINE

02 Aug 1847
SALINE created from GALLATIN by local referendum. (Ill. Laws 1846-1847, priv. and spec., pp. 34-37)
28 Apr 1851
SALINE was abolished by the state legislature; SALINE lost all territory to GALLATIN. (History of Gallatin, Saline, 66-67; Ill. Laws 1851, gen., pp. 28-29)
02 Aug 1852
SALINE re-created from GALLATIN by local referendum. (History of Gallatin, Saline, 66-67; Ill. Laws 1852, pp. 106-108; Ill. Rpts., 12:391-397)
07 Nov 1854
SALINE lost to HAMILTON. (History of Gallatin, Saline, 42-43; Ill. Laws 1853, gen., pp. 265-266; Ill. Laws 1854, priv., pp. 143-144)

SANGAMON

30 Jan 1821
SANGAMON created from BOND and MADISON. (Ill. Laws 1820-1821, pp. 45-46)
31 Jan 1823
SANGAMON lost to creation of MORGAN. (Ill. Laws 1822-1823, pp. 108-109; Ill. Laws 1834-1835, pp. 62-63)
23 Dec 1824
SANGAMON lost to creation of Non-County Area 6. (Ill. Laws 1824-1825, pp. 20-22)
15 Feb 1839
SANGAMON lost to creation of DANE (now CHRISTIAN), LOGAN, and MENARD. (Ill. Laws 1838-1839, pp. 104-107)
02 Mar 1839
SANGAMON lost to MACON. (Ill. Laws 1838-1839, p. 265)
27 Feb 1841
Legislature authorized creation of ALLEN (proposed) from SANGAMON, MACOUPIN, and MORGAN, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, pp. 87-90)
02 Mar 1843
SANGAMON lost to MENARD. (Ill. Laws 1842-1843, p. 94)
28 Feb 1847
SANGAMON lost to MENARD. (Ill. Laws 1846-1847, priv. and spec., p. 39)
15 Feb 1851
Legislature authorized creation of OREGON (proposed) from SANGAMON, MACOUPIN, and MORGAN, dependent on local referendum that failed [no change]. (Ill. Laws 1851, gen., pp. 131-134)

SCHUYLER

13 Jan 1825
SCHUYLER created from FULTON, PIKE, and Non-County Area 3 attached to PIKE. MERCER and WARREN were attached to SCHUYLER. Non-County Area 3 detached from PIKE, attached to SCHUYLER. All attachments were "for all county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
25 Jan 1826
Non-County Area 3 attached to SCHUYLER lost all territory to creation of McDONOUGH; Non-County Area 3 eliminated. McDONOUGH not fully organized, attached to SCHUYLER "for county purposes." (Ill. Laws 1826, pp. 76-77)
01 Mar 1826
MERCER and WARREN detached from SCHUYLER, attached to PEORIA "for county purposes." (Ill. Laws 1826, pp. 76-77)
03 Jul 1830
McDONOUGH fully organized, detached from SCHUYLER. (McLean, 624)
01 Feb 1839
SCHUYLER lost to creation of BROWN. (Ill. Laws 1838-1839, pp. 52-55)

SCOTT

16 Feb 1839
SCOTT created from MORGAN. (Ill. Laws 1838-1839, pp. 126-130)

SHELBY

23 Jan 1827
SHELBY created from FAYETTE; part of FAYETTE became Non-County Area 7 and was attached to SHELBY "until otherwise provided by law." (Ill. Rev. Code 1826-1827, pp. 115-117)
31 Jan 1827
Non-County Area 7 attached to SHELBY lost to creation of TAZEWELL; an additional part of Non-County Area 7 became part of Non-County Area 6 and was attached to TAZEWELL for administrative and judicial purposes. (Ill. Rev. Code 1826-1827, pp. 113-115; Ill. Rev. Code 1828-1829, p. 32)
19 Jan 1829
SHELBY lost all of attached Non-County Area 7 to creation of MACON; Non-County Area 7 eliminated. (Ill. Rev. Code 1828-1829, pp. 28-31)
26 Feb 1839
SHELBY lost to DANE (now CHRISTIAN). (Ill. Laws 1838-1839, pp. 187-188)
24 Feb 1841
Legislature authorized creation of OKAW (proposed) from SHELBY and MACON, dependent on local referendum that failed [no change]. (Ill. Laws 1840-1841, pp. 80-83)
06 Feb 1843
Legislature authorized creation of AUDUBON (proposed) from SHELBY, FAYETTE, and MONTGOMERY, dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 73-74)
16 Feb 1843
SHELBY lost to creation of MOULTRIE. (Ill. Laws 1842-1843, pp. 83-85)
26 Feb 1845
Legislature authorized EFFINGHAM to gain from SHELBY the northern half of township 9 north, ranges 4 to 6 east, dependent on local referendum that failed [no change]. (Ill. Laws 1844-1845, p. 164)
15 Feb 1851
Legislature authorized SHELBY to gain from CHRISTIAN township 11 north, range 1 east, dependent on local referendum that failed [no change]. (Ill. Laws 1851, gen., pp. 118-119)

STARK

02 Mar 1839
STARK created from PUTNAM. On 1 March 1837, an unsuccessful attempt was made to create COFFEE (proposed) in the same general area. (Ill. Laws 1838-1839, pp. 229-232)
18 Mar 1839
STARK gained from KNOX. (Ill. Laws 1838-1839, pp. 229-230)
01 Feb 1840
Legislature authorized STARK to gain from HENRY all of township 14 north, range 5 east; and parts of township 14 north, range 4 east, and township 15 north, ranges 4 and 5 east, dependent on local referendum that failed [no change]. (Ill. Laws 1839-1840, spec. sess., pp. 62-63)
12 Feb 1849
Legislature authorized STARK to gain from HENRY either all of township 14 north, range 5 east, or just the southern half thereof, dependent on local referendum that failed [no change]. (Ill. Laws 1849, 1st sess., gen., pp. 55-56)

STEPHENSON

04 Mar 1837
STEPHENSON created from JO DAVIESS and WINNEBAGO. (Ill. Laws 1836-1837, pp. 96-100)

TAZEWELL

31 Jan 1827
TAZEWELL created from Non-County Area 6 attached to PEORIA and Non-County Area 7 attached to SHELBY. Non-County Area 6 gained from Non-County Area 7, was detached from PEORIA, attached to TAZEWELL for administrative and judicial purposes. (Ill. Rev. Code 1826-1827, pp.113-115; Ill. Rev. Code 1828-1829, p. 32)
25 Dec 1830
TAZEWELL lost to creation of McLEAN and lost part of attached Non-County Area 6 to creation of McLEAN. (Ill. Laws 1830-1831, pp. 57-59)
15 Jan 1831
TAZEWELL lost all of attached Non-County Area 6 to PUTNAM and to the creation of LA SALLE; Non-County Area 6 eliminated. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
27 Jan 1840
TAZEWELL lost to LOGAN. (Ill. Laws 1839-1840, spec. sess., p. 29)
20 Jan 1841
TAZEWELL lost to creation of MASON. (Ill. Laws 1840-1841, pp. 69-71)
27 Feb 1841
TAZEWELL lost to creation of WOODFORD. (Ill. Laws 1840-1841, pp. 84-86)
17 Feb 1843
Legislature authorized WOODFORD to gain from TAZEWELL all of township 26 north, east of the Illinois River (except for small area around East Peoria), dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 86-88)

UNION

02 Jan 1818
UNION created by Illinois Territory from JOHNSON; part of JOHNSON became Non-County Area 1 and was attached to UNION for administrative and judicial purposes. (Ill. Terr. Laws, 292-294)
03 Dec 1818
UNION became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
04 Mar 1819
Non-County Area 1 attached to UNION lost all territory to creation of ALEXANDER; Non-County Area 1 eliminated. (Ill. Laws 1819, pp. 113-114)

Unorganized Federal Territory

01 Mar 1784
All of present Illinois became unorganized federal territory when Virginia ceded its charter claims to the area to the United States. Other claims by Connecticut, Massachusetts, and New York to the area west of Pennsylvania were eliminated by 1786. (Cappon, Petchenik, and Long, 62, 130-131; Hening, 11:571-575)
01 Mar 1784
All of present Illinois became unorganized federal territory when Virginia ceded its charter claims to the area to the United States. Other claims by Connecticut, Massachusetts, and New York to the area west of Pennsylvania were eliminated by 1786. (Cappon, Petchenik, and Long, 62, 130-131; Hening, 11:571-575)
13 Jul 1787
The United States created the Territory of the United States Northwest of the River Ohio (Northwest Territory) from unorganized federal territory. The Northwest Territory was to govern all territory west of Pennsylvania, north of the Ohio River, and east (Terr. Papers U.S., 2:39-50)

VERMILION

18 Jan 1826
VERMILION created from CLARK and Non-County Area 4 attached to EDGAR; Non-County Area 4 detached from EDGAR, attached to VERMILION "for all county purposes." (Ill. Laws 1826, pp. 50-53)
15 Jan 1831
VERMILION lost part of attached Non-County Area 4 to creation of LA SALLE. (Ill. Laws 1830-1831, pp. 54-57, 62-63)
20 Feb 1833
VERMILION lost to creation of CHAMPAIGN and lost part of attached Non-County Area 4 to creation of CHAMPAIGN. (Ill. Laws 1832-1833, priv., pp. 28-30)
26 Feb 1833
VERMILION gained part of Non-County Area 4 attached to it; Non-County Area 4 attached to VERMILION lost to creation of IROQUOIS. IROQUOIS attached to VERMILION "for judicial and other county purposes." (Ill. Laws 1832-1833, priv., pp. 19-20)
24 Feb 1834
IROQUOIS fully organized, detached from VERMILION. (Beckwith, Iroquois, 343)
12 Jan 1836
VERMILION lost part of attached Non-County Area 4 to creation of WILL. (Ill. Laws 1835-1836, pp. 262-263)
27 Feb 1837
VERMILION lost part of attached Non-County Area 4 to creation of LIVINGSTON. (Ill. Laws 1836-1837, pp. 83-85)
21 Feb 1843
Legislature authorized creation of MILTON (proposed) from VERMILION, dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 88-91)
14 Feb 1855
Legislature authorized creation of HARRISON (proposed) from Non-County Area 4 attached to VERMILION, CHAMPAIGN, and McLEAN, dependent on local referendum that failed [no change]. (Ill. Laws 1855, pub., pp. 113-117)
04 Jun 1855
VERMILION lost part of attached Non-County Area 4 to KANKAKEE. (Ill. Laws 1855, priv., pp. 662-663)
31 Jan 1857
Legislature authorized creation of HOLMES (proposed) from CHAMPAIGN, VERMILION, and Non-County Area 4 attached to VERMILION, dependent on local referendum that failed [no change]. (Ill. Laws 1857, pub., pp. 93-98)
05 Apr 1859
VERMILION lost all of attached Non-County Area 4 to creation of FORD; Non-County Area 4 eliminated. (Ill. Laws 1859, pub., pp. 29-33)
09 Jul 1867
Legislature authorized creation of LINCOLN (proposed) from VERMILION and CHAMPAIGN, dependent on local referendum that failed [no change]. (Ill. Laws 1867, priv., 1:868-873)

WABASH

27 Dec 1824
WABASH created from EDWARDS. (Ill. Laws 1824-1825, pp. 25-27)

WARREN

13 Jan 1825
WARREN created from Non-County Area 3 attached to PIKE; WARREN not fully organized, attached to SCHUYLER "for all county purposes." (Ill. Laws 1824-1825, pp. 85-87, 92-96)
01 Mar 1826
WARREN detached from SCHUYLER, attached to PEORIA "for county purposes." (Ill. Laws 1826, pp. 76-77)
27 Jan 1831
WARREN fully organized, detached from PEORIA. MERCER detached from PEORIA, attached to WARREN "for all judicial and other purposes." (Ill. Laws 1830-1831, pp. 67-68)
31 Jan 1835
MERCER fully organized, detached from WARREN. (Ill. Laws 1835-1835, p. 156)
03 Mar 1837
WARREN boundaries were extended to the middle of the Mississippi River [not mapped]. (Ill. Laws 1836-1837, pp. 91-92)
20 Jan 1841
WARREN lost to creation of HENDERSON. (Ill. Laws 1840-1841, pp. 67-69)

WASHINGTON

02 Jan 1818
WASHINGTON created by Illinois Territory from ST. CLAIR. (Ill. Terr. Laws, 312-314)
03 Dec 1818
WASHINGTON became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
27 Dec 1824
WASHINGTON lost to creation of CLINTON. (Ill. Laws 1824-1825, pp. 27-30)

WAYNE (Ind. Terr., extinct)

01 Mar 1803
WAYNE (Indiana Territory, extinct) created by Indiana Territory from KNOX (Ind.), ST. CLAIR, and non-county area; included parts of present Illinois, Indiana, Michigan, Ohio, and Wisconsin. (Ind. Terr., Exec. Journal, 114-115; Pence and Armstrong, 218; U.S. Stat., vol. 2, ch. 40 [1802], secs. 1-3/pp. 173-174; Van Zandt, 112)
30 Jun 1805
WAYNE (Indiana Territory, extinct) eliminated when Michigan Territory was created from Indiana Territory. (Terr. Papers U.S., 10:5-7; U.S. Stat., vol. 2, ch. 5 [1805]/pp. 309-310)

WAYNE (N.W. Terr., extinct)

15 Aug 1796
WAYNE (Northwest Territory, extinct) created by the Northwest Territory from HAMILTON (Ohio), KNOX (Ind.), and non-county area in the Northwest Territory; WAYNE included a small area of present Illinois and parts of present Indiana, Michigan, Ohio, and Wi (Terr. Papers U.S., 2:567-568, 3:447)
04 Jul 1800
WAYNE (Northwest Territory, extinct) was eliminated from present Illinois when Indiana Territory was created from the Northwest Territory. (Terr. Papers U.S., 3:86-88; U.S. Stat., vol. 2, ch. 41 [1800]/pp. 58-59)

WAYNE

26 Mar 1819
WAYNE created from EDWARDS. (Ill. Laws 1819, pp. 268-269)
14 Feb 1821
WAYNE lost to creation of FAYETTE. (Ill. Laws 1820-1821, pp. 164-167)
23 Dec 1824
WAYNE lost to creation of CLAY. (Ill. Laws 1824-1825, pp. 18-20)
22 Jan 1829
WAYNE boundaries were clarified [no change]. (Ill. Rev. Code 1828-1829, p. 32)
21 Feb 1863
Legislature authorized CLAY to gain from WAYNE the southern half of township 2 north, ranges 5 to 8 east, dependent on local referendum that failed [no change]. (Ill. Laws 1863, pub., pp. 84-85)

WHITESIDE

16 Jan 1836
WHITESIDE created from HENRY and JO DAVIESS; WHITESIDE not fully organized, attached to JO DAVIESS until "organized." (Ill. Laws 1835-1836, 273-278)
24 Dec 1836
WHITESIDE detached from JO DAVIESS, attached to OGLE "for all judicial and county purposes." (History of Ogle, 299-300; Ill. Laws 1835-1836, p. 277)
21 Feb 1839
WHITESIDE fully organized, detached from OGLE. (Ill. Laws 1838-1839, pp. 143-144)
04 Mar 1854
WHITESIDE exchanged with ROCK ISLAND. (Ill. Laws 1853, priv., p. 462; Ill. Laws 1854, priv., pp. 161-162)
29 Mar 1869
WHITESIDE exchanged with ROCK ISLAND (repealed act of 4 March 1854). (Ill. Laws 1869, pub., pp. 94-95, 161)

WHITE

01 Feb 1816
WHITE created by Illinois Territory from GALLATIN; boundary with GALLATIN is estimated. (Ill. Terr. Laws, 185-186)
02 Jan 1818
WHITE lost to creation of FRANKLIN. (Ill. Terr. Laws, 290-291)
03 Dec 1818
WHITE became a county in the state of Illinois when Illinois was created from Illinois Territory. (Terr. Papers U.S., 10:803; U.S. Stat., vol. 3, ch. 67 [1818], secs. 1-2, 7/pp. 428-429, 431, and res. 1 [1818]/p. 536)
26 Mar 1819
WHITE lost to creation of JEFFERSON. (Ill. Laws 1819, pp. 267-268)
08 Feb 1821
WHITE lost to creation of HAMILTON. (Ill. Laws 1820-1821, pp. 113-114)
07 Nov 1854
WHITE gained from GALLATIN. (History of Gallatin, Saline, 42-43; Ill. Laws 1853, gen., pp. 265-266; Ill. Laws 1854, priv., pp. 143-144)

WILLIAMSON

05 Aug 1839
WILLIAMSON created from FRANKLIN. (Ill. Laws 1838-1839, pp. 110-113)

WILL

12 Jan 1836
WILL created from COOK, IROQUOIS, Non-County Area 9, and Non-County Area 4 attached to VERMILION. (Ill. Laws 1835-1836, pp. 262-263)
Aug 1839
The legislature authorized DU PAGE to gain the northern halves of township 37 north, ranges 9 and 10 east, from WILL, dependent on local referendum that failed [no change]. (History of Will, 358-359; Ill. Laws 1838-1839, pp. 73-74)
11 Feb 1851
Legislature authorized creation of KANKAKEE from WILL and IROQUOIS, dependent on local referendum that failed [see 5 April 1853]. (Ill. Laws 1851, gen., pp. 30-35)
05 Apr 1853
WILL lost to creation of KANKAKEE. (Ill. Laws 1853, gen., pp. 159-163)

WINNEBAGO

16 Jan 1836
WINNEBAGO created from JO DAVIESS and Non-County Area 8 attached to LA SALLE. (Ill. Laws 1835-1836, 273-278)
04 Mar 1837
WINNEBAGO lost to creation of BOONE and STEPHENSON. (Ill. Laws 1836-1837, pp. 96-100)
22 May 1843
WINNEBAGO lost to BOONE. (Ill. Laws 1842-1843, p. 92)

WOODFORD

27 Feb 1841
WOODFORD created from McLEAN and TAZEWELL. (Ill. Laws 1840-1841, pp. 84-86)
17 Feb 1843
Legislature authorized WOODFORD to gain from TAZEWELL all of township 26 north, east of the Illinois River (except for small area around East Peoria), dependent on local referendum that failed [no change]. (Ill. Laws 1842-1843, pp. 86-88)
28 Feb 1843
WOODFORD exchanged with McLEAN. (Ill. Laws 1842-1843, p. 91)