Illinois is a Democratic stronghold in presidential elections and one of the "Big Three" Democratic strongholds alongside California and New York. It is one of the most Democratic states in the nation with all state executive offices and both state legislative branches held by Democrats.[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. Louis.[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.
The following table indicates the party of elected officials in the U.S. state of Illinois:
^The Office of Illinois Auditor of Public Accounts existed from 1818-1973, when it was eliminated by the 1970 Constitution and replaced with the office of Comptroller. George W. Lindberg was the first Illinois Comptroller
^Andrew Jackson received two of Illinois's three electoral votes for President while John Quincy Adams received one. John C. Calhoun won all three electoral votes for Vice President.
^Due to the ascension of Lt. Gov. Beveridge to the Governorship after Gov. Oglesby took a U.S. Senate seat, the President Pro Tempore elected by the Senate, John Early, became acting Lt. Governor.[5]
^A coalition of Democrats and Independents organized the Senate, and chose Archibald A. Glenn, a Democrat, to be President Pro Tempore. Due to the vacancy in the Lt. Governorship from John Beveridge ascending to be Governor in 1873, Glenn also became acting Lt. Governor.[5]
^A coalition of Democrats and Independents organized the House, and chose Elijah Haines, a Independent, to be Speaker.[5]
^A coalition of Democrats and Independents organized the Senate, and chose Fawcett Plumb, an Independent tied to the Farmers' Association, to be President Pro Tempore.[5]
^The Independent, Elijah Haines, was elected Speaker with Democratic support, giving them control.
^With the support of the Progressive members, the Democrats named the President Pro Tempore and controlled the chamber.
^After 76 ballots, a Democrat, William B. McKinley, was elected Speaker with Republican votes.[6]
^With the support of the Progressive member, the Democrats named the President Pro Tempore and controlled the chamber.
2018 Illinois gubernatorial election. Strong Democratic turnout in Chicago, Cook County, all of the suburban collar counties, and modest growth in downstate support (mainly in the smaller cities) drove J. B. Pritzker's decisive victory.
