Illinois is a blue state, and has been reliably so for more than three decades. Democrats have carried it in every presidential election since 1992, hold all six statewide constitutional offices, run supermajorities in both chambers of the state legislature, and control 14 of the state’s 17 U.S. House seats. In 2024, Kamala Harris beat Donald Trump in Illinois by about 11 points.1AP News. 2024 Illinois Election Results
Nine Straight Democratic Presidential Wins
Illinois has voted Democratic in nine consecutive presidential elections, from Bill Clinton in 1992 through Harris in 2024.2270toWin. Illinois Presidential Election Voting History For most of the 20th century the state was a bellwether that backed Ronald Reagan twice and George H.W. Bush in 1988. The shift began in 1992, as Chicago kept posting overwhelming Democratic margins and the suburbs started moving in the same direction.
Joe Biden took roughly 57.5% of the Illinois vote in 2020. Harris won 54.4% to Trump’s 43.5% in 2024, a tighter result in line with national trends, but the state was never genuinely competitive.1AP News. 2024 Illinois Election Results
Democrats Hold Every Statewide Office
The Democratic edge runs through state government. All six constitutional officers are Democrats: the Governor, Lieutenant Governor, Attorney General, Secretary of State, Comptroller, and Treasurer. Governor J.B. Pritzker unseated Republican incumbent Bruce Rauner in 2018 and won re-election comfortably in 2022. Rauner’s single term is the only Republican statewide victory in Illinois in over a decade.
In the legislature, Democrats hold roughly 41 of 59 Illinois Senate seats and around 73 of 118 Illinois House seats. Those are veto-proof supermajorities. The party can pass legislation without Republican votes.
A Lopsided Congressional Delegation
Illinois’s 17-member U.S. House delegation splits about 14 Democrats to 3 Republicans as of 2025. Voter preferences produce most of that gap; redistricting widens it. Illinois is one of the states where the legislature draws congressional maps subject to the governor’s signature.3All About Redistricting. Who Draws the Lines With Democrats controlling both chambers and the governor’s office, they drew the post-2020-census map on their own. The state lost a seat to population decline, dropping from 18 districts to 17, and Democrats still projected seat gains under the new lines.4All About Redistricting. Illinois
Chicago Sets the Math
Cook County, home to Chicago and many inner suburbs, holds about 40% of the state’s population. Biden won roughly 74% of the Cook County vote in 2020. A margin that large from the state’s population center is a deficit no Republican has been able to make up with rural strength.
Downstate Illinois votes very differently. Outside the Chicago metropolitan area, most counties are solidly Republican. Springfield, Champaign, and Bloomington lean more moderate, but the surrounding farm and exurban communities are deep red. In a state without a single dominant metro, those rural margins could be decisive. In Illinois, they fall short.
The Suburban Flip That Sealed It
Chicago alone did not turn Illinois reliably blue. The suburbs did. The five collar counties around Cook, DuPage, Lake, Will, Kane, and McHenry, were once Republican strongholds, and DuPage in particular was considered the center of suburban Republicanism in the Midwest.
That era is over. In 2000, none of the five collar counties gave the Democratic presidential nominee a majority. By 2020, four of the five did. In 2024, DuPage County gave Harris nearly 57% of its vote.5DuPage County. 2024 General Election Official Abstract of Votes Between 2014 and 2022, Democrats improved their gubernatorial performance across the collar counties by 10 to 20 points. With those suburbs gone, statewide Republicans have no arithmetic path back.
Demographics Keep It That Way
Several factors reinforce the pattern. The Chicago metro area has a racially and ethnically diverse electorate that broadly favors Democrats. Educational attainment in urban and suburban Illinois runs high, and the collar counties are among the most educated in the Midwest, which correlates nationally with Democratic voting. The state also has a significant share of union households in the trades and public sector.
These factors compound. Young professionals and immigrants concentrate in metro Chicago, the suburbs move further left, Republican statewide candidates struggle to build a coalition, recruitment suffers, and the cycle continues. Breaking it would take a major national realignment or a Republican who can win back educated suburban voters.
Red Parts of a Blue State
Calling Illinois a blue state describes how it votes as a whole, not how every part of it votes. Large stretches of downstate Illinois vote Republican by wide margins in nearly every election, and Republicans still win local offices, legislative seats, and House districts in those areas. The state result comes out blue because Chicago and its suburbs together outweigh the rest.