See main article: 1868 United States presidential election.
| Election Name: | 1868 United States presidential election in Illinois |
| Country: | Illinois |
| Flag Year: | 1864 |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1864 United States presidential election in Illinois |
| Previous Year: | 1864 |
| Next Election: | 1872 United States presidential election in Illinois |
| Next Year: | 1872 |
| Election Date: | November 3, 1868 |
| Image1: | Ulysses S Grant by Brady c1870-restored (3x4 crop).jpg |
| Nominee1: | Ulysses S. Grant |
| Party1: | Republican Party (United States) |
| Home State1: | Illinois |
| Running Mate1: | Schuyler Colfax |
| Electoral Vote1: | 16 |
| Popular Vote1: | 250,304 |
| Percentage1: | 55.69% |
| Nominee2: | Horatio Seymour |
| Party2: | Democratic Party (United States) |
| Home State2: | New York |
| Running Mate2: | Francis Preston Blair, Jr. |
| Electoral Vote2: | 0 |
| Popular Vote2: | 199,116 |
| Percentage2: | 44.31% |
| Map Size: | 350px |
| President | |
| Before Election: | Andrew Johnson |
| Before Party: | Democratic Party (United States) |
| After Election: | Ulysses S. Grant |
| After Party: | Republican Party (United States) |
The 1868 United States presidential election in Illinois took place on November 3, 1868, as part of the 1868 United States presidential election. Voters chose 16 representatives, or electors to the Electoral College, who voted for president and vice president.
Illinois voted for the Republican nominee, Ulysses S. Grant, over the Democratic nominee, Horatio Seymour. Grant won his home state by a margin of 11.38%.