AAR, my atlas doesn't show a Port City, and it lists some pretty small towns. I used to live in S. E. Kansas, and that's why Ponca City came to mind. I've never heard of a Port City Oklahoma, but I'm not an expert on Oklahoma by any means! You might try getting ahold of Oklahoma Dept. of Motor Vehicles and see if they can do a hand search for previous registrations in Oklahoma. Several states will do that for a small fee. Good luck in your search!