Illinois Treasurer Michael Frerichs said the checks will arrive in the mail in coming days.
Checks went out to roughly 140,000 people as part of the latest round of the Enhanced Money Match program.
The program allows the State to return money from things like old bank accounts, or overpaid utility bills, without people having to file a claim.
The state treasurer said many people don't think the checks are real.
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So far, more than $13 million have been returned to people in Illinois.
The State said the Treasurer is holding more than $5 billion in unclaimed funds for Illinoisans.
To learn more about the program, click here.