Tulsa is the second-largest city in the State of Oklahoma and 47th-largest city in the United States. As of July 2013 the population was 398,121, an increase of 6,215 over that reported in the 2010 Census. It is the principal municipality of the Tulsa Metropolitan Area, a region with 961,561 residents in the MSA and 1,131,458 in the CSA. The city serves as the county seat of Tulsa County, the most densely populated county in Oklahoma, and extends into Osage, Rogers, and Wagoner counties.Tulsa was first settled between 1828 and 1836 by the Lochapoka Band of Creek Native American tribe. For most of the 20th century, the city held the nickname "Oil Capital of the World" and played a major role as one of the most important hubs for the American oil industry.Once heavily dependent on the oil industry, economic downturn and subsequent diversification efforts created an economic base in the energy, finance, aviation, telecommunications and technology sectors. The Tulsa Port of Catoosa, at the head of the McClellan-Kerr Arkansas River Navigation System, is the most inland river port in the U.S. with access to international waterways. Two institutions of higher education within the city have sports teams at the NCAA Division I level, Oral Roberts University and the University of Tulsa.