Closest U.S. Senate elections in Illinois

The tightest U.S. Senate races Illinois has held, ranked by the margin between the top two candidates.

The closest U.S. Senate election in Illinois history was in 1914, a margin of 1.7 points. Lawrence Y. Sherman beat Roger C. Sullivan, 390,661 to 373,403. Next closest are 1984 (1.9 points) and 1998 (2.9 points).

Every state is ranked together on Closest U.S. Senate elections in history. For every Senate race Illinois has held, special elections included, see the Illinois U.S. Senate hub.

What is the closest Senate race in Illinois history?

The Illinois Senate election decided by the narrowest margin was in 1914, 1.7 points. Lawrence Y. Sherman beat Roger C. Sullivan, 390,661 to 373,403. The next closest were 1984 (1.9 points) and 1998 (2.9 points).

How is the margin measured?

As the gap in vote share between the first and second-place finishers, from the certified general-election count. It is not adjusted for recounts, runoffs or later court rulings; the figure is the result as certified.

Does this include special elections?

No. These are the regular general elections for Illinois’s two Senate seats. Special elections to fill a vacancy appear on the Illinois Senate hub, which lists every race including specials, and in a few states one of those is closer than anything here.

Why does the list start in 1914?

Because senators were chosen by state legislatures before the Seventeenth Amendment. 1914 is the first cycle of the popular-vote era for the Senate, so it is the first Illinois election with a popular margin to measure.

Closest U.S. Senate elections in Illinois
#ElectionResultVotesMargin
11914Lawrence Y. Sherman R def. Roger C. Sullivan D390,661 – 373,4031.7 points
21984Paul Simon D def. Charles H. Percy R2,397,165 – 2,308,0391.9 points
31998Peter G. Fitzgerald R def. Carol Moseley-Braun D1,709,041 – 1,610,4962.9 points
41938Scott W. Lucas D def. Richard J. Lyons R1,638,162 – 1,542,5743.0 points
51926Frank L. Smith R def. George E. Brennan D842,273 – 774,9433.7 points
61944Scott W. Lucas D def. Richard J. Lyons R2,059,023 – 1,841,7935.5 points
71918Medill McCormick R def. J. Hamilton Lewis D479,983 – 426,9435.6 points
81962Everett M. Dirksen R def. Sidney R. Yates D1,961,202 – 1,748,0075.7 points
91966Everett M. Dirksen R def. William G. Clark D2,358,947 – 2,073,2426.4 points
101942C. Wayland Brooks R def. Raymond S. McKeough D1,582,887 – 1,380,0116.8 points
111954Paul H. Douglas D def. Joseph T. Meek R1,804,338 – 1,563,6837.1 points
121978Charles H. Perey R def. Alex Smith D1,698,711 – 1,448,1877.9 points
131950Everett M. Dirksen R def. Scott W. Lucas D1,951,984 – 1,657,6308.1 points
141956Everett M. Dirksen R def. Richard Stengel D2,307,352 – 1,949,8838.4 points
151960Paul H. Douglas D def. Samuel W. Witwer R2,530,943 – 2,093,8469.4 points
161992Carol Moseley-Braun D def. Richard S. Williamson R2,631,229 – 2,126,83310.2 points
171948Paul H. Douglas D def. C. Wayland Brooks R2,147,754 – 1,740,02610.5 points
182014Richard J. Durbin D def. James D. Jim Oberweis R1,929,637 – 1,538,52210.9 points
191932Wiliiam H. Dietrich D def. Otis F. Glenn R1,882,304 – 1,432,84113.3 points
201980Alan J. Dixon D def. David C. O'Neal R2,565,302 – 1,946,29613.5 points
212016Tammy Duckworth D def. Mark Steven Kirk R3,012,940 – 2,184,69215.1 points
221968Adlai Stevenson III D def. Ralph Tyler Smith R2,065,054 – 1,519,71815.2 points
232022Tammy Duckworth D def. Kathy Salvi R2,329,136 – 1,701,05515.3 points
241996Richard J. Durbin D def. Al Salvi R2,384,028 – 1,728,82415.4 points
251936J. Hamilton Lewis D def. Otis F. Glenn R2,142,887 – 1,545,17015.8 points

How this ranking is measured

U.S. Senate general elections in Illinois, ranked by the smallest gap in vote share between the top two finishers, 1914 to the present, closest 25 shown. Served from the senate_race_margin materialized view. Special elections are excluded, and so is any contest where the top two did not draw at least 1,000 votes between them or where the recorded winner was not the vote leader. The national list of the closest Senate races anywhere applies a 50,000-vote floor, which is why a small early race can appear here and not there.

Compiled by PolitiFinder · published June 14, 2026 · sources: Data & sources · data last verified September 25, 2026.