See main article: 1856 United States presidential election.
| Election Name: | 1856 United States presidential election in Illinois |
| Country: | Illinois |
| Flag Year: | 1856 |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1852 United States presidential election in Illinois |
| Previous Year: | 1852 |
| Next Election: | 1860 United States presidential election in Illinois |
| Next Year: | 1860 |
| Election Date: | November 4, 1856 |
| Image1: | James Buchanan (cropped).jpg |
| Nominee1: | James Buchanan |
| Party1: | Democratic Party (United States) |
| Home State1: | Pennsylvania |
| Running Mate1: | John C. Breckinridge |
| Electoral Vote1: | 11 |
| Popular Vote1: | 105,528 |
| Percentage1: | 44.09% |
| Nominee2: | John C. Frémont |
| Party2: | Republican Party (United States) |
| Home State2: | California |
| Running Mate2: | William L. Dayton |
| Electoral Vote2: | 0 |
| Popular Vote2: | 96,275 |
| Percentage2: | 40.23% |
| Image3: | Fillmore (cropped).jpg |
| Nominee3: | Millard Fillmore |
| Party3: | Know Nothing |
| Home State3: | New York |
| Running Mate3: | Andrew J. Donelson |
| Electoral Vote3: | 0 |
| Popular Vote3: | 37,531 |
| Percentage3: | 15.68% |
| Map Size: | 350px |
| President | |
| Before Election: | Franklin Pierce |
| Before Party: | Democratic Party (United States) |
| After Election: | James Buchanan |
| After Party: | Democratic Party (United States) |
The 1856 United States presidential election in Illinois took place on November 4, 1856, as part of the 1856 United States presidential election. Voters chose 11 representatives, or electors to the Electoral College, who voted for president and vice president.
Illinois voted for the Democratic candidate, James Buchanan, over Republican candidate John C. Frémont and American Party candidate Millard Fillmore. Buchanan won Illinois by a narrow margin of 3.86%.
This would be the final time a Democratic presidential candidate would win Illinois until Grover Cleveland won it in 1892.