House districts / Illinois
Illinois's 12th congressional district
IL-12. Same lines in 2026 as in 2022.
Fundraising
- Michael Bost Ras of Oct 14, 2026Raised $1.6mSpent $1.1m · Cash $845k
- Julie Fortier Das of Oct 14, 2026Raised $162kSpent $128k · Cash $34k
1 other 2026 candidate filed reports (primary candidate).
Federal Election Commission, candidate totals, public domain.
President in this district
PollCheck calculation from precinct returns on the 2026 lines (method).
| Year | Democrat | Republican | Other | Margin |
|---|---|---|---|---|
| 2024 | Harris 27.4% | Trump 70.6% | 2.0% | R+43.2 |
| 2020 | Biden 27.7% | Trump 70.5% | 1.8% | R+42.8 |
| 2016 | Clinton 26.0% | Trump 68.5% | 5.5% | R+42.5 |
Who lives here
| Measure | This district | US |
|---|---|---|
| People | ||
| Population | 746,831 | |
| Adults (18+) | 585,229 | |
| Citizens, % of adults | 98.7% | 92.1% |
| Age, % of adults | ||
| 18 to 29 | 17.8% | 20.3% |
| 30 to 44 | 23.8% | 25.9% |
| 45 to 64 | 33.1% | 31.8% |
| 65 and over | 25.3% | 22.0% |
| Race and Hispanic origin, % of residents | ||
| White | 87.2% | 57.4% |
| Black | 4.8% | 11.9% |
| Hispanic | 3.1% | 19.3% |
| Asian | 1.0% | 5.9% |
| Other or more than one | 3.9% | 5.5% |
| Education and income | ||
| Bachelor's degree or higher, % of 25+ | 24.4% | 35.7% |
| Median household income | $68,540 | $80,734 |
American Community Survey 2020-2024 5-year estimates for this district. The tick marks the US figure.
Winning margin
Results since 1976
| Year | Winner | Share | Runner-up | Share | Margin |
|---|---|---|---|---|---|
| Current lines (2022 on) seat count changed from 18 to 17 after the census | |||||
| 2024 | Mike Bost Republican | 74.2% | Brian Roberts Democrat | 25.8% | R+48.4 |
| 2022 | Mike Bost Republican | 75.0% | Homer “Chip” Markel Democrat | 25.0% | R+50.0 |
| Earlier lines, elections 2012-2020 seat count changed from 19 to 18 after the census | |||||
| 2020 | Mike Bost Republican | 60.4% | Raymond C. Lenzi Democrat | 39.6% | R+20.9 |
| 2018 | Mike Bost Republican | 51.6% | Brendan Kelly Democrat others 3.0% | 45.4% | R+6.2 |
| 2016 | Mike Bost Republican | 54.3% | Charles "C. J." Baricevic Democrat others 6.0% | 39.7% | R+14.6 |
| 2014 | Mike Bost Republican | 52.5% | William L. Enyart Democrat others 5.7% | 41.9% | R+10.6 |
| 2012 | William L. Enyart Democrat | 51.6% | Jason Plummer Republican others 5.6% | 42.7% | D+8.9 |
| Earlier lines, elections 2002-2010 seat count changed from 20 to 19 after the census | |||||
| 2010 | Jerry F. Costello Democrat | 59.8% | Teri Newman Republican others 3.6% | 36.5% | D+23.3 |
| 2008 | Jerry F. Costello Democrat | 71.4% | Timmy Jay Richardson Jr. Republican others 3.7% | 24.9% | D+46.5 |
| 2006 | Jerry F. Costello Democrat | 100.0% | D+100.0 | ||
| 2004 | Jerry F. Costello Democrat | 69.5% | Erin R. Zweigart Republican others 1.7% | 28.9% | D+40.6 |
| 2002 | Jerry F. Costello Democrat | 69.2% | David Sadler Republican | 30.8% | D+38.5 |
| Earlier lines, elections 1992-2000 seat count changed from 22 to 20 after the census | |||||
| 2000 | Jerry F. Costello Democrat | 100.0% | D+99.9 | ||
| 1998 | Jerry F. Costello Democrat | 60.4% | William Melvin Price Republican | 39.6% | D+20.7 |
| 1996 | Jerry F. Costello Democrat | 71.6% | Shapley R. Hunter Republican others 1.8% | 26.6% | D+45.0 |
| 1994 | Jerry F. Costello Democrat | 65.9% | Jan Morris Republican | 34.1% | D+31.8 |
| 1992 | Jerry F. Costello Democrat | 71.2% | Mike Starr Republican | 28.8% | D+42.5 |
| Earlier lines, elections 1982-1990 seat count changed from 24 to 22 after the census | |||||
| 1990 | Philip M. Crane Republican | 82.2% | Steve Pedersen Solidarity | 17.8% | R+64.4 |
| 1988 | Philip M. Crane Republican | 75.2% | John A. Leonardi Democrat | 24.8% | R+50.4 |
| 1986 | Philip M. Crane Republican | 77.7% | John A. Leonardi Democrat | 22.3% | R+55.4 |
| 1984 | Philip M. Crane Republican | 77.8% | Edward J. LaFlamme Democrat | 22.2% | R+55.6 |
| 1982 | Philip M. Crane Republican | 66.2% | Daniel G. DeFosse Democrat others 3.1% | 30.7% | R+35.5 |
| Earlier lines, elections 1976-1980 | |||||
| 1980 | Philip M. Crane Republican | 74.1% | David McCartney Democrat | 25.9% | R+48.2 |
| 1978 | Philip M. Crane Republican | 79.5% | Gilbert Bogen Democrat | 20.5% | R+59.1 |
| 1976 | Philip M. Crane Republican | 72.8% | Edwin L. Frank Democrat | 27.2% | R+45.7 |
More on Illinois
Other Illinois districts
About these results
Shares count all candidate votes, including write-ins, with a candidate's votes on several party lines added together. Each result is on the lines in force at the time. Mid-decade redraws before 2016 may be unmarked.
President in this district: 2016 and 2020 are estimates: precinct votes are split between districts by census block.
Counties only partly inside the district show the 2024 result for that part; estimates are labelled.
Margin chart: winner minus runner-up. Gaps are unopposed races; dashed lines are new district lines.
Sources
Results: MIT Election Data and Science Lab, U.S. House 1976-2016 (doi:10.7910/DVN/IG0UN2, CC0; via MEDSL/constituency-returns), and Clerk of the US House, Statistics of the Presidential and Congressional Election 2018-2024 (public domain).
Presidential results: PollCheck calculation from MIT Election Data and Science Lab 2024 precinct returns (doi:10.7910/DVN/XDJYKC, doi:10.7910/DVN/USBYR4, CC0; state totals doi:10.7910/DVN/42MVDX, CC0) and Voting and Election Science Team 2016 and 2020 precinct results and shapes (doi:10.7910/DVN/NH5S2I, doi:10.7910/DVN/K7760H, CC BY 4.0), with US Census Bureau 2020 block populations and block equivalency files (public domain). Official figures: Texas Legislative Council (2024 on the 2026 lines); Louisiana, New Jersey, California and Washington election offices (county totals). Certified results transcribed by Wikipedia (CC BY-SA 4.0): Maine 2024 by district: 2024 United States presidential election in Maine (revision 1382530995); Indiana county totals: 2024 United States presidential election in Indiana (revision 1382505975); Oregon county totals: 2024 United States presidential election in Oregon (revision 1382605746).
District lines: US Census Bureau TIGER/Line 2026 (120th Congress) and 2025 cartographic boundary files (119th Congress), public domain.
Members: unitedstates/congress-legislators (CC0).
Counties: US Census Bureau 2024 cartographic boundary file (public domain); 2024 county results summed from the same MEDSL precinct returns, with the official county totals above.
Demographics: US Census Bureau, American Community Survey 5-year estimates 2020-2024 (public domain).
2028 candidates: Federal Election Commission (public domain).
Photos: official portraits, public domain (US government); see Photo credits.
PollCheck US. Data through November 5, 2026. Photo credits