Illinois in the American Civil War

During the American Civil War, the state of Illinois was a major source of troops for the Union Army (particularly for those armies serving in the Western Theater of the Civil War), and of military supplies, food, and clothing. Situated near major rivers and railroads, Illinois became a major jumping-off place early in the war for Ulysses S. Grant's efforts to seize control of the Mississippi and Tennessee rivers. Statewide, public support for the Union was high despite pockets Copperhead sentiment among some antiwar Democrats.

The state was energetically led throughout the war by Governor Richard Yates. Illinois contributed 250,000 soldiers to the Union Army, ranking it fourth in terms of the total manpower in Federal military service. Illinois troops predominantly fought in the Western Theater, although a few regiments played important roles in the East, particularly in the Army of the Potomac. Several thousand Illinoisians were killed or died of their wounds during the war, and a number of national cemeteries were established in Illinois to bury their remains. In addition to President Abraham Lincoln, a number of other Illinois men became prominent in the army or in national politics, including generals, Ulysses S. Grant, John M. Schofield and John A. Logan, Senator Lyman Trumbull, and Representative Elihu P. Washburne. No major battles were fought in the state, although several river towns became sites for important supply depots and "brownwater" navy yards. Several prisoner of war camps and prisons dotted the state after 1863, processing thousands of captive Confederate soldiers.

The war was highly controversial in Southern Illinois—known as "Little Egypt." There was some support for the Confederacy but mostly it was a matter of fierce opposition to Lincoln's war policies. The most dramatic episode came when Congressman John A. Logan switched from opposition to a national leader in support of the war,