The last time that Illinois voted Republican for President was in 1988.
From the Civil War through the 1920s, Illinois voted Republican. During the Great Depression and through World War II, the state changed, and voted Democratic. It returned to its Republican roots from 1952 through 1988, the last election where the state voted Republican. The last five elections has seen Illinois voting “blue.” In 2008, now-President Barack Obama easily beat Senator John McCain in Illinois.
The state used to be a powerhouse in the Midwest, with the most electoral votes, but Illinois has been steadily losing its electoral votes over the past 40 years. During the 2010 census, Illinois lost one electoral vote, giving it only 20 for the 2012-2020 Presidential elections. The state used to have 29 electoral votes at its peak in the 1930s.