In Iowa, vehicle registration is handled by your local county treasurer’s office. You will get a notification of your renewal by mail from your county treasurer. You are required to renew your vehicle registration in your county of residence. You may renew your registration online at https://www.iowatreasurers.org. Residents in 9 counties use the Tax and Tags system (Buchanan, Dickinson, Floyd, Iowa, Johnson, Linn, Montgomery, Polk, and Poweshiek).