Nope, Ohio, with an o.
Now, there are some people who say Cincinnati or Missouri like Cincinnatah, Missourah. In fact my pastor at church this morning said "Missourah." Cracked me up. He's from New York. I think he tries to change his speech sometimes so he sounds local. Fail.
But, you've gotta know the correct way to pronounce Louisville, KY. Quiz: Short answer, let's hear it.