[1][2] For most of its history, Illinois was widely considered to be a swing state, voting for the winner of all but two presidential elections in the 20th century.
Political party strength in Illinois is highly dependent upon Cook County, and the state's reputation as a blue state rests upon the fact that over 40% of its population and political power is concentrated in Chicago, Cook County, and the Chicago metropolitan area.
Outside of Chicago, the suburban collar counties continue trending Democratic[3] while downstate Illinois can be considered more conservative with several Democratic leaning regions including Champaign-Urbana, Bloomington-Normal, Rockford, Peoria, the Quad Cities, and suburban St.
[4] Illinois's electoral college votes have gone towards the Democratic presidential candidate for the past eight elections, and its congressional makeup tilts heavily Democratic with a 14-3 majority as of 2025.
However, it has a history of competitive statewide elections and has elected a small number of moderate Republicans including Governors Jim Edgar, George Ryan, and Bruce Rauner, Senators Peter Fitzgerald and Mark Kirk, and other state executive officeholders including Judy Baar Topinka and Dan Rutherford.