Phillipe Renault brought the first slaves into the French-held Illinois country in 1720; and although their descendants were finally freed by the courts in 1845, their presence caused political and legal problems until the Civil War.

The imaginative and seminal Northwest Ordinance of 1787 established guidelines for the creation of states in the large triangle of land between the Ohio and Mississippi rivers and the Great Lakes and supposedly banned slavery in what became Illinois. However, that provision was evaded by a system of indenture, established during the territorial period and reinforced by the state legislature, permitting Negroes to be registered as servants, often for terms exceeding their lifetimes. Children born to the indentured servants were bound to the mother's master for terms of 30 years for males and 28 years for females. An attempt to repeal the indenture laws was vetoed in 1817 by the territorial governor, Ninian Edwards.

The fact that the first four governors held registered servants is one indication that proslavery feeling itself was strong in Illinois. The actual number of slaves was never large, with only 917 recorded in 1820, 746 in 1830, and 331 in 1840. Between 1000 and 2000, however, were regularly leased from Southern owners to work on the federal salt reservation near Shawneetown under a constitutional provision allowing slaves there until 1825.

The man most responsible for the defeat of the proslavery forces was the state's second governor, Edward Coles. Coles freed his own slaves when he arrived in Illinois in 1819, and after three years as registrar of the Edwardsville land office he ran as the antislavery candidate for governor. Two candidates split the proslavery vote, and Coles took office.

Proslavery legislators soon recommended a referendum to hold a convention and change the state constitution to allow slavery. In the year and a half before the issue came to a vote in 1824, Coles organized a massive effort to defeat the proposal. Organizing an antislavery society, he financed the campaign out of his gubernatorial salary. He found important allies in Englishman Morris Birkbeck and Baptist Missionary John Mason Peck. Proslavery forces were led by former Gov. Shadrach Bond; Jesse Thomas and Elias Kent Kane (both important in the convention which wrote the constitution of 1818); and the state's first congressman, John McLean.

The contest was one of the most heated in Illinois history, with the antislavery, anticonvention forces emerging victorious by a vote of 6640 to 4972. Pseudo-slavery in the form of indenture continued until the Civil War; but this was the last attempt to make Illinois an official, constitutional, slave state. The antislavery forces disbanded after this victory, and did not pursue a solution to the problems created by Southern slavery on Illinois soil or racial and legal barriers to equality.