Polls opened at 6 a.m. and were scheduled to close at 7 p.m.
Suburban voters are going to the polls to elect mayors, village presidents, trustees, aldermen, as well as seats on library boards, park districts and school boards.
One of the most high-profile races is in the 2nd Congressional District. Voters will chose a replacement for Jesse Jackson Jr., who resigned last year amid a federal investigation and health concerns.
Democratic nominee Robin Kelly is considered to be the frontrunner. Kelly, a former state lawmaker from Matteson, voted Tuesday morning then went to the Metra stop at 147th Street in Harvey to get out the vote.
"I just really feel my breadth of experience, the skills I bring to the table, my education, all of that wrapped into one makes me the best candidate," Kelly said.
Kelly faces Republican challenger Paul McKinley, Green Party candidate LeAlan Jones and independent candidates Marcus Lewis, Curtiss Bey and Elizabeth Pahlke.
Some voters in the heavily Democratic 2nd District are still wounded by Jesse Jackson Jr.'s admission to misusing campaign funds.
"We thought for years that we could really trust him," said 2nd District voter Jocelyne Wright. "But things happened, I guess, and we just need to go for the person we feel is right for us."
Meanwhile, roughly three-quarters of Chicago-area suburbs will elect mayors or village presidents. Hundreds of other offices are also up for grabs.
In one high-profile race, former Chicago Bear Steve McMichael is running against incumbent Romeoville Mayor John Noak.
In north suburban Mettawa, Casey Urlacher, the brother of former Chicago Bears' linebacker Brian Urlacher, is running against village trustee Jeff Clark.
And, in Arlington Heights, three candidates are squaring off to replace longtime mayor Arlene Mulder, who is not running for reelection. Ron Drake has the endorsement of U.S. Senator John McCain. He is running against public interest lawyer Mark Hellner and village trustee Thomas Hayes.
For more information on candidates, check out: ABC7's Online Meet the Candidates Forum.
Election results also will be available here.