Counties beginning early voting Thursday include Kane, Kendall, Lake, McHenry and Wil.
Chicago will offer early voting beginning February 12 at 137 South State and 69 West Washington.
On March 2, it starts in all 50 wards.
2026 primary elections: Click here for voter information in Illinois, Indiana, Wisconsin
For suburban Cook County, early voting begins March 2, depending on where you live.
SEE ALSO: US Postal Service changes could delay mail-in ballots for upcoming Illinois primary election
For people in DuPage County, leaders there say early and vote-by-mail options will begin later this month - instead of today - because election officials say they are waiting for rulings on unresolved candidate objections.
Voters will decide on a number of high-stakes congressional races in this election, that haven't been open in years - including:
Outgoing Senator Dick Durbin's seat, Congresswoman Jan Schalowsky's 9th district seat, Congressman Danny Davis' 7th district seat, and Congressman Chuy Garcia's 4th district seat.
Eighth District Congressman Raja Krishnamoorthi and 2nd District Congresswoman Robin Kelly are both in the race for Durbin's senate seat - so their seats in the house will also be open.
Primary Election Day is March 17.The General Election is on November 3 of this year.