Postponed Property Taxes Due July 31: The second half installment of the 2023 property taxes ( payable in 2024) are due July 31, 2024 to the Columbia County Treasurer. Payments can be mailed to the following address. Treasurer P.O. Box 198 112 E Edgewater St Portage, WI 53901 Online payments may be made also. Instructions for Online Real Estate Payments