The Polls opened up in Ohio this morning and will remain open until 7:30 PM tonight. Be sure to check that your polling station as not changed via the BOE website's poll search.
If you have an absentee ballot, you can still return it, but it must be received by the Board of Elections before 7:30 PM tonight. You best bet is to hand deliver it. The Hamilton County Board of Elections is located at 824 Broadway, Cincinnati, OH 45202.