Iowa: Commentary

Iowa 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 2007

Before Statehood

The land within the present state of Iowa was part of the Louisiana Purchase, acquired in 1803 from France. In 1804, it was incorporated into the District of Louisiana, which was attached to Indiana Territory. Subsequently present Iowa was part of Louisiana Territory (1805–1812) and Missouri Territory (1812–1821). It became unorganized federal territory when Missouri became a state in 1821, and continued so until it became part of Michigan Territory in 1834. In 1836 present Iowa was incorporated into Wisconsin Territory and remained there until 3 July 1838, when Iowa Territory was created from Wisconsin Territory. The state of Iowa was created on 28 December 1846, with its present boundaries. The maps in this digital atlas show all of the county configurations under these various jurisdictions.

Iowa’s County Boundaries

The land that became the state of Iowa was once part of the national public domain and, as such, was divided for sale according to the federal rectangular survey system. Although some of the earliest county creations and boundary changes in present Iowa were based on river systems and arbitrary lines, lawmakers quickly recognized the utility of basing boundaries on the survey system. Thus the Missouri territorial legislature began incorporating range and township lines into county boundary descriptions early in its governance of present Iowa, and that practice has been continued by subsequent governing bodies. The lines laid down by those early land surveyors are still in use and remain a prominent and important feature of the modern maps used to make this atlas. Given the persistence of the survey lines and their appearance on modern federal maps, plotting county lines based on the land survey is easier and more precise than working with metes and bounds descriptions that depend on ridge lines, river systems, and local landmarks.

A few boundary lines cannot be precisely drawn. Some involve natural features or local landmarks that are difficult to locate, while a few reflect the vagueness and imprecision of the laws on which they are based. Occasionally a boundary line cannot be drawn as described, due to some oversight or error in the legislation or typographical error in the printed statute. The legislature's intent is usually apparent in other provisions of the law in question or in later boundary changes, and in these cases the intent of the law—rather than a rigid interpretation of the text—has been followed.

The Iowa state constitution of 1857 (still in effect, as amended) stipulates that no new county can be created containing less than 432 square miles and that no existing county can be reduced below that size by boundary changes. The 1857 constitution exempted from these requirements Worth County and the counties west of Worth along the Minnesota border, which had been created in 1851 and were smaller than 432 square miles: Bancroft (eliminated in 1855), Dickinson, Emmet, Osceola, and Winnebago (Art. XI, sec. 2). The constitution of 1846 also had the 432-square-mile requirement, but no one challenged the constitutionality of the six counties created in 1851. An 1844 draft constitution, which accompanied Iowa Territory's application for statehood and which was rejected by the voters, would have required a county minimum of 400 square miles. Both the 1846 and 1857 constitutions required that all boundary changes between existing counties be approved by the voters of each affected county in a general election. In practice, very few boundary changes were submitted to the voters for approval; the legislature usually altered the boundaries of existing counties by simply defining or redefining the county boundaries.

Two cases involving these constitutional provisions were ultimately decided by the Iowa State Supreme Court. In 1860 the court voided an 1858 act transferring four townships from Webster County to Humboldt County because the transfer had not been submitted to the voters for approval. The 1857 act re-creating Humboldt had, through a printing error, failed to include the four townships in Humboldt. An 1858 "explanatory" act had corrected the error, but the court ruled that it was an "independent" act and did "not relate back" to the 1857 law. Thus, according to the constitution of 1857, it was subject to voter approval. The four townships therefore reverted to Webster County.

In the second case, an 1871 ruling, the court found the 1870 creation of Crocker County unconstitutional. Crocker was created from Kossuth County with the same, identical boundaries as Bancroft County, which was eliminated in 1855. While Crocker contained only 408 square miles, it was equal in size to Worth and the five counties west of Worth (including the now-extinct Bancroft County) exempted from the constitutional minimum of 432 square miles. The court ruled that Worth and the counties west of it could be organized with no additional territory, but that no new county could be created with an area less than 432 square miles. Crocker was considered a new county and, therefore, not constitutionally acceptable.

In 1862 the legislature provided for local initiative in altering county boundaries. If at least one-half of the legal voters in each of the affected counties petitions their county board of supervisors for a change, the proposed change must be presented for a vote at the next general election. If a majority of the voters in each affected county approve, the boundary change takes effect on the first Monday of January following the election. Another law, approved in 1864, allows local residents to rename their county. If one-fifth of the county's legal voters petition their board of supervisors for a name change, the supervisors propose a name, which the voters consider at the next general election.

Prior to Iowa statehood in 1846, both the Wisconsin and Iowa territorial legislatures immediately “attached” newly-created counties to fully organized counties, but beginning in 1846 Iowa frequently left counties "unorganized" at creation. At a later date, the legislature either attached them to an organized county or fully "organized" them (i.e., made provisions for county government). In 1847 the state legislature extended the procedure for organizing Pottawattamie County to all unorganized counties: whenever the judge of the judicial district in which an unorganized county was located deemed that the "public good" required that the county be organized, he could order a special election to select the first county officers. An 1853 law provided that an unorganized county could be organized when a majority of the legal voters of an unorganized county petitioned the county judge of the county to which the unorganized county was attached, and the judge, in turn, was required to order the election of the first county officers.

The process by which unorganized territory was attached to organized counties changed over time, could last for a period of several months to several years, and contained many ambiguities. Furthermore, the precise nature of the attachments is not always clear; in some cases the unorganized area was simply "attached" to an existing county, but in other instances the attachments were "for temporary purposes," "for judicial purposes," or "for election, revenue, and judicial purposes." While it is beyond the scope of this project to define the precise meaning of each phrase, the variations in terminology may be important to researchers. Therefore, when the purpose of the attachment is stated in the law, it is included in both the consolidated chronology and the individual county chronology in quotation marks (e.g., "for judicial purposes"). In cases where the law gives no specific purpose for the attachment, the phrase for administrative and judicial purposes is used without quotation marks.

These different approaches to creating, attaching, and organizing counties are reflected in the fact that only 16 (including the re-created Humboldt County) of Iowa's present 99 counties were fully organized at creation and were never attached to another county. Of the remaining 83 counties, 63 were attached to another county at some point (17 at creation and 46 subsequent to creation). The other 20 counties were not fully organized at creation but were subsequently organized without ever being attached to another county.

Although territorial and state officials generally respected Indian rights to the land and often incorporated Indian boundary lines in county boundaries, as early as 1837 the Wisconsin territorial legislature extended county lines in present Iowa to the western limits of the territory. It thus anticipated the migration of non-Indian settlers into the region well before the Sioux tribes ceded the last Indian lands in northwestern and north-central Iowa in 1851. In this digital atlas, the county boundaries are drawn as described in the laws, with due regard to the Indian boundary lines when they were part of the boundary description—but with no recognition of the gradual purchase of Indian lands by territorial and state officials.

A boundary dispute between Iowa and Missouri was ultimately settled by the United States Supreme Court in 1849. Missouri precipitated the controversy in 1838 when it expanded its Clark County north of the line commonly accepted as the boundary since 1820—the modern boundary, known since 1816 as the "Old Indian Boundary" or "Sullivan line." Missouri's 1838 encroachment overlapped just a small part of Iowa's Van Buren County, but in 1839 Missouri enlarged the area by claiming a strip of land, approximately ten miles wide, north of the present boundary, between the Des Moines and Missouri Rivers.

In 1846 Congress referred the boundary dispute to the United States Supreme Court. The dispute hinged on the location of the "rapids" of the Des Moines River, from which point the northern boundary of Missouri was to run due west and to "correspond with the Indian boundary line"—according to the Missouri constitution of 1820. In arguing its case before the Supreme Court in 1847, Missouri located the "rapids" of the Des Moines River approximately ten miles north of the present boundary. Iowa contended that the "rapids," as they were commonly recognized in 1820, were in the Mississippi River—not the Des Moines River. Iowa's interpretation put the boundary approximately seven miles south of the present line. In its decision of 13 February 1849, the Supreme Court rejected both claims, asserting that there were no actual rapids in the Des Moines River, and dismissing as untenable Iowa's claim that the rapids in question were in the Mississippi River. Instead, the Court chose the Indian boundary line run and marked by John C. Sullivan in 1816, which was the commonly accepted boundary before the dispute arose and which remains the present boundary between the two states.

In this digital atlas, only the 1838 overlap of Van Buren County, Iowa by Clark County, Missouri is mapped, since the boundaries of the overlap are clearly defined in a Missouri law. However, the county overlaps implicit in Missouri's definition of its northern boundary in 1839 and in the boundaries advocated by the two states before the United States Supreme Court in 1847 are not mapped because the proposed boundaries were never extended to the county level. These "implicit" overlaps are covered in the chronologies only.

Most Iowa laws creating new counties or altering the boundaries between existing counties took effect upon passage of the law. In some cases an effective date was stated in the law, and after 1855 some laws took effect after they were published in two state newspapers (named in the law). Organization dates (i.e., the date, after creation, when a county became fully operational and independent) for Iowa counties are taken from two sources. Forty-two counties were organized by statute, either at creation (16) or at a later date (26). The other 57 were organized under the judicial procedures outlined in the 1847 and 1853 election laws. Organization dates for those 57 counties are taken from Jacob A. Swisher, "Organization of Counties": organization dates for 49 counties use the date of the county's first official business; dates for 6 counties (Dickinson, Emmet, Hardin, Monona, Sac, and Story) are the election of the first county officers; and dates for the counties of Sioux and Winnebago are approximate, since Swisher could find no specific date of organization.


Virtually all boundary changes in Iowa, from its earliest days as part of the District of Louisiana to the present, have been made by the successive legislatures that have controlled the area. The Territorial Papers of the United States and the territorial laws of the governments responsible for the area of present Iowa are indispensable sources for tracing Iowa's territorial history. The session laws for Iowa Territory, Laws of the Territory of Iowa, and for the state, Acts and Joint Resolutions of the State of Iowa, are available in printed volumes and in microform. These sources are supplemented by specialized collections cited in the source citations and bibliography.