Tennesseans who want to vote by mail this election must register today. Post offices will be closed Monday for Columbus Day, which is also the last day to register to vote in person. Only Lewis and Hickman county election offices will be closed Monday. All others will be open for last-minute registrations. Eight driver service centers will open Saturday to issue photo IDs to allow voters to comply with a new state law requiring identification for casting ballots. The offices will be in Davidson, Hamilton, Knox, Madison, Putnam, Shelby, Washington and Weakley counties.