How long does it take to mail a letter to get from Cleveland Ohio to Columbus Ohio?

Standard mail time. Could be 3 days, could be a week. Depending on if you use bulk mail (check it out, you end up paying less per envelope but will the USPS really be motivated to give you priority?) or a standard 1st class postage stamp. Also will depend on the volume of mail at that time of year. The Christmas season will almost guarantee to take a week. etc etc. BUT, in an average week it should get there in only a few days.