Tulsa/ˈtʌlsə/ is the second-largest city in the state of Oklahoma and 47th-most populous city in the United States. As of July 2015, the population was 403,505, an increase of 11,599 over that reported in the 2010 Census. It is the principal municipality of the Tulsa Metropolitan Area, a region with 981,005 residents in the MSA and 1,151,172 in the CSA. The city serves as the county seat of Tulsa County, the most densely populated county in Oklahoma, with urban development extending into Osage, Rogers, and Wagoner counties.
Tulsa was 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.
It is situated on the Arkansas River at the foothills of the Ozark Mountains in northeast Oklahoma, a region of the state known as "Green Country". Considered the cultural and arts center of Oklahoma, Tulsa houses two world-renowned art museums, full-time professional opera and ballet companies, and one of the nation's largest concentrations of art deco architecture. The city has been called one of America's most livable large cities by Partners for Livable Communities, Forbes, and Relocate America. FDi Magazine in 2009 ranked the city no. 8 in the U.S. for cities of the future. In 2012, Tulsa was ranked among the top 50 best cities in the United States by BusinessWeek. People from Tulsa are called "Tulsans".