Dallas, with an estimated population nearing 1.3 million, the city is the main economic center of the 12-county Dallas–Fort Worth–Arlington metropolitan area that according to the March 2009 U.S. Census Bureau release, had a population of 6,300,066 as of July 2008, making it the number one metropolitan area in population growth in the nation last year. It is also the center of the largest metro area in Texas. Dallas is rated as a beta world city by the Loughborough University Globalization and World Cities Study Group & Network. Founded in 1841 and formally incorporated as a city in February, 1856, the city's economy is primarily based on banking, commerce, telecommunications, computer technology, energy, and transportation. Located in North Texas and a major city in the American South & Southwest, Dallas is the core of the largest inland metropolitan area in the United States that lacks any navigable link to the sea. The city's prominence despite this comes from its historical importance as a center for the oil and cotton industries, its position along numerous railroad lines, a strong industrial and financial sector, and its status as a major inland port (due largely to the presence of Dallas-Fort Worth International Airport, one of the largest and busiest in the world).