Dallas / ˈ d æ l ə s /  is a major city in  Texas  and along with  Fort Worth , is one of the two urban centers of  a metropolitan area  that ranks fourth in the  United States . The city proper ranks  ninth in the U.S.  and  third in Texas . [4] [5]  The city’s prominence arose from its historical importance as a center for the oil and cotton industries, and its position along numerous railroad lines. The bulk of the city is in  Dallas County , of which it is the county seat. However, sections of the city are located in  Collin ,  Denton ,  Kaufman , and  Rockwall  counties. According to the  2010 United States Census , the city had a population of 1,197,816. [6]  The  United States Census Bureau ‘s estimate for the city’s population increased to 1,241,162 as of 2012. [7]  

The city is the largest economic center of the 12-county  Dallas–Fort Worth–Arlington  metropolitan area, which had a population of 6,810,913 as of July 1, 2013. [8]  The metropolitan economy is the sixth largest in the United States, with a 2012 real GDP of $420.34 billion. [9]  In 2013 the metropolitan area led the nation with the largest year-over-year increase in employment, and advanced to become the fourth-largest employment center in the nation (behind  New York City ,  Los Angeles  and  Chicago ) with more than three million non-farm jobs. [10]  In the latest rankings released in 2013, Dallas was rated as a “beta plus”  world city  by the  Globalization and World Cities Study Group & Network . [11]  Dallas is also ranked 14th in world rankings of GDP by the  Organisation for Economic Co-operation and Development .

Dallas was 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, healthcare and medical research, transportation and logistics. The city is home to the third-largest concentration of  Fortune 500  companies in the nation. [12]  Located in  North Texas , Dallas is the main core of the largest inland metropolitan area in the United States that lacks any navigable link to the sea. [13]

It was developed because of construction of major railroad lines here; it became a hub in 1873. It was connected to Houston and other major cities that were railroad cities. It was booming by the late 19th and early 20th century, and was the world center of leather manufacture and harnessmaking. The interstate highway system in the 1950s and 1960s reinforced and consolidated Dallas’ prominence. As with the railroads, east/west and north/south highways converged here. Four major interstate highways converge in the city, and a fifth interstate loops around it. Dallas developed a strong industrial and financial sector, and a major  inland port , due largely to the presence of  Dallas/Fort Worth International Airport , one of the largest and  busiest airports  in the world. [14]