2012 United States presidential election in Illinois

The 2012 United States presidential election in Illinois took place on November 6, 2012, as part of the 2012 United States presidential election in which all 50 states plus the District of Columbia participated. Illinois voters chose 20 electors to represent them in the Electoral College via a popular vote pitting incumbent Democratic President Barack Obama and his running mate, Vice President Joe Biden, against Republican challenger and former Massachusetts Governor Mitt Romney and his running mate, Congressman Paul Ryan. The Obama/Biden ticket won Illinois with 57.50% of the popular vote to Romney/Ryan's 40.66%, thus winning the state's twenty electoral votes by a margin of 16.84%.

Obama's victory continued a Democratic winning streak in the state — with the Democratic candidate having carried Illinois through six consecutive elections. However, despite Obama's win in 2008 and popularity in the state due to being its former U.S. Senator, his performance significantly worsened, with his margin of victory decreasing from 25.10% to 16.84% and losing 23 counties to Romney that he had won four years prior. Obama further became the first ever Democrat to win the White House without carrying Gallatin or Macoupin Counties, as well as the first since Woodrow Wilson in 1916 to win the White House without carrying Madison County. While Obama only won 23% of the counties in Illinois, most of the counties he won were heavily populated. His 17-point victory can be largely attributed to his performance in Cook County, which encompasses the Chicago Metropolitan Area. He also won the once Republican-favored collar counties (DuPage, Will and Lake). He also performed well in the East St. Louis area.

As of the 2020 presidential election, this is the last time a Democrat has won Alexander, Carroll, Fulton, Henderson, Henry, Jo Daviess, Knox, Mercer, Putnam, Warren, and Whiteside counties.