A head to head comparison of the 2008 Illinois General Election gives us an idea of the break down of the voters.
Barack Obama received 3,419,673 (62%) votes, beating John McCain who gained 2,031,527 (37%) by 1,388,146 votes in Illinois.
John McCain won 56 counties whereas Barack Obama won 46 counties in the total of the 102 counties in the State of Illinois.
2008 General Election Barack Obama Popular Vote Count Contributed by Illinois (IL)
Presidential General Elections
During the 2008 General elections, over 131M total number of votes were cast. Barack Obama got 69,448,278 (69.4 Million) over John McCain's 61,739,059 (61.7 Million). He won the popular vote by 7,709,219 (7.7 Million). His victory in the State of Illinois (with 3,419,673 votes) represents 4.7% of his popular vote victory. The remaining 49 states contributed to the remaining 95.3% popular votes victory.
Top 15 Counties in Primary Elections vs General Elections
All Candidates (General Elections)
These 15 counties play an important role in these Primary elections. If a candidate, can get a sizable majority in the largest counties (Cook, Dupage, Lake, Will), it becomes very difficult to win majorities in the smaller counties without voter outreach and increased voter participation in them.
Top 15 Counties Comparison in Primary Elections vs General Elections
Cook, Dupage, Lake and Will, four of the larger counties, voted in favor of Barack Obama giving him a 1.2 Million vote advantage. However, John McCain's steady marginal wins in the less popular counties were not enough to overcome that deficit, making him gain an upper hand in the State of Illinois.
Related References: 2016 Illinois Primary Election Story, 2016 Illinois General Election Story, 2020 Illinois Primary Election Story, 2020 Illinois General Election Story, 2012 Illinois General Election Story