Mormons

Joseph Smith and fellow members of the Mormon church arrived in western Illinois in the late 1830s after facing violent antagonism in Ohio and Missouri. Smith purchased the town of Commerce from a land speculator who had secured land from the United States government after the forced removal of Meskwaki from the area. Smith oversaw the draining of the swampy region, renamed the town Nauvoo, and began constructing a temple. The town's population grew until hostility from nearby residents started brewing again in 1844.

The following three manuscript letters recount the incarceration and subsequent murder of Joseph Smith in nearby Carthage, Illinois. The earliest, from 1843, makes mention of the possibility of more Mormons coming to the area soon. The last two, from 1844, describe Smith’s arrest, death, and the subsequent migration of the Mormons from Nauvoo westward.

...We are in continual fear of the Mormons they have sworn very [?] against us, there has been an army of about two thousand men here in order to force the execution of the laws which have been so long trodden under foot by the Mormons. They destroyed a printing press at Nauvoo … Jo and his b. Hiram were killed by a party of men from Missouri[?] who overpowered the guard and shot them both … Mormons are getting out of the country as fast as possible.” (letter dated July 1, 1844)

Icarians

After Mormons were expelled from Nauvoo, much of the town's housing stood vacant. A group of Icarians purchased buildings in Nauvoo to establish a permanent settlement after failing to start a colony in Texas. A utopian movement founded in France, the Icarians embraced the principles of equality and communal living espoused in Étienne Cabet's novel, Voyage en Icarie (Voyage to Icaria). The following newspaper clippings, court documents, and letters relate to the founding by Icarians of communities in Nauvoo, Illinois as well as their subsequent move westward to Corning, Iowa, after going bankrupt.

The Brief History of Icaria details the history, bylaws, and legislation of the Icarians, describing on page six the rise and fall of the colony at Nauvoo:

[Cabet] set out with 280 persons for Nauvoo, a small Illinois village on the Mississippi, which had been abandoned by the Mormons. They arrived there on the 15th of March, 1849. From that date an era of prosperity—too short, alas!—dawned upon Icaria. Workshops were opened, farms were hired and purchased, a flouring and saw-mill put in operation, a tailor's shop established, schools founded, a theater, choirs and an orchestra organized... But new misfortunes awaited the colony in its path of fortune. A political tempest overthrew the entire edifice.