Illinois · 2026 forecast · Updated Oct 16, 2026
39 of 59 seats are on the ballot; the others are elected in alternate years. 30 seats make a majority. 36 make the three-fifths supermajority that can override a veto.
Democrats are very likely to control the Illinois State Senate (>99%).
Democratic supermajority now (40 of 59 seats; 36 needed for three-fifths): >99% chance it holds · <1% chance it's broken.
40 D nowMarks: three-fifths supermajority for each party19 R now
Democrats are very likely to control the Illinois State Senate (>99%).
Democratic supermajority now (40 of 59 seats; 36 needed for three-fifths): >99% chance it holds · <1% chance it's broken.
40 D nowMarks: three-fifths supermajority for each party19 R now
All 39 races, grouped by the leader's chance of winning.
3 seats projected to flip: 3 R→D.
3 seats projected to flip: 3 R→D.
Columns follow the chance of winning: Toss-up 40–60%, Lean 60–80%, Likely 80–95%, Solid 95%+. The square shows who holds the seat now (■ Democrats, ■ Republicans). flip: projected to change parties, in the color of the party favored to gain it. Faded: no major-party opponent.
Each district colored by the leader's chance of winning. Hover for details; click for the race.
Illinois
Chicago
The closest races (Lean or Toss-up, Horizon), and the seats most likely to change parties.
Rules that shape these races and the forecast.
Senators serve terms of two or four years in a set pattern each decade, so a different share of the seats is on the ballot each election: 39 of 59 in 2026.
39 of 59 seats on the ballot; 20 holdovers (17 D, 3 R) serve until a later election.
Chance of winning control, by forecast date.
Updated nightly. Each day is the current model run on the polls that had ended by then (how).
Updated nightly. Each day is the current model run on the polls that had ended by then (how).
Democratic seats across 40,000 simulations. Darker bars: the middle 80%.
39 races, 22 without a contest between the major parties.
| District | Candidates | Chance of winning (D · R) | Avg. margin | Rating | Lean | Polls |
|---|---|---|---|---|---|---|
| LD-2 | ● Omar AquinoINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+61 | — | |
| LD-3 | ● Mattie HunterINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+71 | — | |
| LD-5 | ● Lakesia CollinsINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+70 | — | |
| LD-6 | ● Sara FeigenholtzINC● Frank Rowder | D+69.4D+73.3 | D+68 | — | ||
| LD-8 | ● Ram VillivalamINC● Vince Romano | D+36.5D+28.0 | D+22 | — | ||
| LD-9 | ● Patrick Hanley● Tom Lally | D+56.8D+59.5 | D+54 | — | ||
| LD-11 | ● Mike PorfirioINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+23 | — | |
| LD-12 | ● Celina VillanuevaINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+45 | — | |
| LD-14 | ● Emil Jones IIIINC● Brian Skala | D+49.1D+46.9 | D+41 | — | ||
| LD-15 | ● Napoleon HarrisINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+50 | — | |
| LD-17 | ● Elgie SimsINC● Frederick L. Walls | D+66.4D+67.4 | D+63 | — | ||
| LD-18 | ● No Democrat● Christine McGovernAlso: Frances Ann Hurley (I) | No Democrat on the ballotNo Democrat on the ballot | — | D+10 | — | |
| LD-20 | ● Graciela GuzmánINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+65 | — | |
| LD-21 | ● Laura EllmanINC● Julie Berkowicz | D+32.7D+30.5 | D+24 | — | ||
| LD-23 | ● Suzy Glowiak HiltonINC● Linda Polacek | D+24.4D+21.0 | D+14 | — | ||
| LD-24D flipD flip | ● Benjamin "Ben" McAdams● Seth LewisINC | D+8.6D+11.7 | D+5 | — | ||
| LD-26D flipD flip | ● Nabeela Syed● Darby HillsINC | D+13.7D+15.7 | D+9 | — | ||
| LD-27 | ● Carina Santa Maria● David Mathis | D+28.2D+26.0 | D+19 | — | ||
| LD-29 | ● Julie A. MorrisonINC● Kate McGrath | D+46.4D+41.0 | D+35 | — | ||
| LD-30 | ● Adriane JohnsonINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+36 | — | |
| LD-32 | ● No Democrat● Craig WilcoxINCAlso: Karen Battaglia (I) | No Democrat on the ballotNo Democrat on the ballot | — | R+6 | — | |
| LD-33 | ● No Democrat● Danielle PenmanAlso: Michele Clark (I) | No Democrat on the ballotNo Democrat on the ballot | — | D+3 | — | |
| LD-35 | ● No Democrat● Dave SyversonINCAlso: Sarah B. Mertens (I) | No Democrat on the ballotNo Democrat on the ballot | — | R+9 | — | |
| LD-36 | ● Michael HalpinINC● Brad Beekman | D+17.2D+11.0 | D+6 | — | ||
| LD-38 | ● No Democrat● Sue RezinINCAlso: Ernie R. Marcelain (I) | No Democrat on the ballotNo Democrat on the ballot | — | R+7 | — | |
| LD-39 | ● Don HarmonINC● No Republican | Democrat unopposedDemocrat unopposed | — | D+46 | — | |
| LD-41 | ● No Democrat● John CurranINC | Republican unopposedRepublican unopposed | — | D+9 | — | |
| LD-42 | ● Linda HolmesINC● Edgardo "Eddie" PerezAlso: Jared Ploger (D) | D+32.8D+29.4 | D+23 | — | ||
| LD-44 | ● No Democrat● Sally J. TurnerINC | Republican unopposedRepublican unopposed | — | R+29 | — | |
| LD-45 | ● No Democrat● Andrew ChesneyINCAlso: Joseph H. "Joe" Berning (I) | No Democrat on the ballotNo Democrat on the ballot | — | R+22 | — | |
| LD-47 | ● No Democrat● Neil AndersonINC | Republican unopposedRepublican unopposed | — | R+31 | — | |
| LD-48 | ● Doris TurnerINC● Frank Lesko | D+15.8D+10.0 | D+4 | — | ||
| LD-50 | ● No Democrat● Jil TracyINC | Republican unopposedRepublican unopposed | — | R+46 | — | |
| LD-51 | ● No Democrat● Chapin RoseINC | Republican unopposedRepublican unopposed | — | R+45 | — | |
| LD-53 | ● No Democrat● Chris BalkemaINC | Republican unopposedRepublican unopposed | — | R+35 | — | |
| LD-54 | ● No Democrat● Steve McClureINC | Republican unopposedRepublican unopposed | — | R+45 | — | |
| LD-56D flipD flip | ● Marsia Geldert-Murphey● Erica HarrissINC | D+2.8D+4.2 | R+2 | — | ||
| LD-57 | ● Christopher BeltINC● Daniel Rhyne | D+24.0D+17.4 | D+12 | — | ||
| LD-59 | ● Tamiko "T.C." Mueller● Paul JacobsINC | R+27.7R+30.3 | R+36 | — |
Lean: how much more Democratic (D+) or Republican (R+) the place voted for president than the nation (2024 weighted 75%, 2020 25%). Ratings follow the chance of winning: Toss-up 40–60%, Lean 60–80%, Likely 80–95%, Solid 95%+. INC = incumbent running. D flip / R flip: another party is favored (60% or more) over the party holding the seat now (hover for the chance it changes parties); Flip risk: the seat is a toss-up (40–60%).