The second-largest city in Oklahoma is Tulsa, which has five letters. Tulsa is located in the northeastern part of the state and is the county seat of Tulsa County. It is the principal municipality of the Tulsa Metropolitan Area, a region with 991, 005 residents in the MSA and 1, 251, 172 in the CSA. The city serves as the cultural and economic center of the region. Tulsa has a rich history, having been founded in 1836 by the Lochapoka Band of Creek Native American tribe. It has since grown to become the second-largest city in Oklahoma, with a population of over 400, 000 people.