Notices to property owners identified as qualified for the refunds will be mailed this month, Pappas said in a news release.
"If they file for refunds, these owners could receive a check that would provide some relief for holiday budgets," Pappas said.
About 8,500 owners of Cook County homes, businesses and land had paid property taxes for which they had been billed.
However, when the assessed valuation of their property was lowered, that change caused their first installment payment to exceed what was due.
This qualified them for refunds totaling some $9.8 million -- an average of about $1,140 per property, Pappas said.
Even before the mailed notices arrive, Cook County property owners can see if they qualify for a refund by checking the treasurer's Web site or calling 312-443-5100, Pappas said.