Great Plains National Bank Address: 101 S Oklahoma Ave, Mangum, OK 73554 Phone: (580) 782-5555 Banks Other Businesses: First National Bank & Trust Co at 204 N Oklahoma Ave, Mangum, OK 73554 Stockman's Bank at 1400 N Louis Tittle Ave, Mangum, OK 73554 Duffer Motel at 2003 N Louis Tittle Ave, Mangum, OK 73554 Hamburger Inn at 126 S Pennsylvania Ave, Mangum, OK 73554