The first installment of Colusa County Property Taxes are now due and payable. If not paid by 5 p.m., Monday, December 12, 2011, a 10% penalty will be added to each installment. Payments received in the mail must be postmarked on or before Monday, December 12, 2011. Payments can be made at the Treasurer/Tax Collector’s Office, 547 Market St., Suite 111, Colusa, CA, 95932.