Today, Illinois is considered the “Land of Lincoln”, but prior to the Civil War, it straddled the line between slave state and free.
That Illinois would help elect the “Great Emancipator” was not a foregone conclusion. For much of its early history, Illinois had a close relationship with slavery and was openly hostile to abolitionism. Yet, by 1860, enough voters embraced the Republican Party to elect Abraham Lincoln president, a change that was hugely consequential for African American freedom, and the nation as a whole.
Populated by immigrants from Virginia, Kentucky, and Tennessee, Illinois entered the Union in 1818 with strict black codes on the books. The Illinois Constitution prohibited the introduction of slavery, but permitted residents already holding slaves to keep their property. As historian Suzanne Guasco explained, Illinois was “the only state created out of the Old Northwest Territory that failed to abolish slavery outright during its constitutional convention.”
Missouri, bordering Illinois to the west, came into the Union as a slave state in 1821. Kentucky, Illinois’ neighbor to the south, was also a slave state. The Mississippi River connected Illinois economically with other slave holding states to the south, and the bottom third of Illinois lay below the cultural Mason-Dixon Line. It’s a little-known fact that slave labor was used in at least one southern Illinois industry.
Though Article 6 of the Northwest Ordinance banned slavery in Illinois, as did the Illinois Constitution of 1818, an exception was made for the Gallatin County salt mines. By 1819, the Gallatin County salines produced nearly 300,000 bushels of salt. Approximately 1,000 black slaves worked the mines and processed the salt.
John Hart Crenshaw (1797-1871), owner of the salt mines and those slaves, built a large plantation home on Hickory Hill, not far from the ironically named Equality, Illinois. His salt operation at one time contributed a third of the state’s annual tax income. It’s also alleged he was part of the Reverse Underground Railroad, sending captured slaves south back to bondage.
According to historian James Simeone, the slave issue became a rhetorical device Illinois politicians exploited to win votes. In February 1823, the Illinois House of Representatives passed a resolution calling for a convention to revise the state constitution with the aim of legalizing the slave trade in Illinois. Illinois Governor Edward Coles, himself a former slaveholder from Virginia, opposed the resolution.
When the convention resolution was put to a popular vote, a record 95 percent of registered voters turned out to decide the issue. In the end, 57 percent, most of whom were persuaded by the argument that the induction of a slave trade would harm free white labor, rejected the resolution. 
The vote was far from an endorsement of abolitionism. In fact, Illinois abolitionists were routinely attacked by their opponents. Elijah Lovejoy, a prominent newspaper editor and abolitionist from Missouri who moved to Illinois to escape pro-slavery partisans, had his printing press destroyed by mobs three times. He was murdered in Alton in 1837 for defending his press from a mob.
In 1848, Illinois voters adopted a new state constitution, which included a provision banning free blacks from entering the state. Article XIV read:
“The general assembly shall, at its first session under the amended constitution, pass such laws as will effectually prohibit free persons of color from immigrating to and settling in this state; and to effectually prevent the owners of slaves from bringing them into this state for the purpose of setting them free.”
The Illinois General Assembly didn’t act on Article XIV until 1853, when it passed the harshest Black Laws in the North. Democratic State Representative John A. Logan, who later became a Radical Republican and strong supporter of President Abraham Lincoln, introduced the legislation. Frederick Douglass observed that a “nation of savages… could not be guilty of more inhuman and barbarous legislation.”
In 1858, the Chicago Daily Times openly proclaimed that Illinois was “known all over the Union as a state where white people are absolute and supreme.” But public attitudes were changing.
Debate over the Kansas-Nebraska Act created an opportunity for a new anti-slavery political party, which emerged in the Upper Midwest. The Republican Party was not abolitionist, per se (though it had abolitionist members), but it officially opposed the expansion of slavery into new states and territories. Its slogan was “Free soil. Free labor. Free men.”
When the Whig Party collapsed in 1854 over the issue of slavery, politicians like Abraham Lincoln found themselves without a home. A small nucleus of Illinois Republicans led by Owen Lovejoy, brother of murdered abolitionist Elijah Lovejoy, recruited these former Whigs into their burgeoning party. At first, their efforts met resistance everywhere but in the northernmost counties of Illinois. Lincoln helped bring in voters from downstate and recruited German immigrants who predominantly settled in northern Illinois.
In the 1856 presidential election, Democratic candidate James Buchanan narrowly won the state with a 3.86 percent margin over the popular free-labor exponent John C. Fremont. Republican William H. Bissell won the governorship with a slimmer margin. In the 1860 U.S. presidential election, Republican Abraham Lincoln defeated Democrat Stephen A. Douglas in Illinois by only 3.52 percent of the popular vote.
Lincoln’s narrow margin of victory doesn’t tell the whole story, however. Illinois had become politically bifurcated, with northern counties overwhelmingly voting for Abraham Lincoln and southern counties overwhelmingly voting for Stephen Douglas.
That all of Illinois would stand behind the new President was not a foregone conclusion. When the Civil War broke out, some counties in southern Illinois talked openly about joining the Confederacy. Stephen Douglas rushed home to persuade them to stand with the Union. “There can be no neutrals in this war,” he said, “only patriots―or traitors.” His words ended any talk of secession, and Illinois remained firmly in the Union camp. The rest, they say, is history.
In 1955, Illinois officially adopted the slogan “Land of Lincoln,” and it’s hard to take a step today without seeing a public tribute to our sixteenth president. History, however, tells a more complicated tale, the course of which is often decided by a precariously slim margin.
 Suzanne Cooper Guasco, “’The Deadly Influence of Negro Capitalists’: Southern Yeomen and Resistance to the Expansion of Slavery in Illinois” Civil War History 47 (Winter 2001): 13.
 James Simeone, Democracy and Slavery in Frontier Illinois: the Bottomland Republic (DeKalb: Northern Illinois University Press, 2000), 106.
 Guasco, 26.
 “The Black Law of Illinois,” Frederick Douglass’ Paper (Rochester) 18 March 1853.
 “The Election: its Consequences,” Daily Times (Chicago) 2 October 1858.
 William E. Gienapp, The Origins of the Republican Party, 1852-1856 (New York: Oxford University Press, 1987), 122-126.
 Howard W. Allen and Vincent A. Lacey, eds., Illinois Elections, 1818-1990: Candidates and County Returns for President, Governor, Senate, and House of Representitives (Carbondale: Southern Illinois University Press, 1992), 10-11.
 Wood Gray, The Hidden Civil War: The Story of the Copperheads (New York: The Viking Press, 1942), 57-9.