The Dallas–Fort Worth metroplex is the fourth-largest metropolitan region in the United States, with a population of 7.5 million people, and the most populated city within it is Dallas. In the U.S. state of Texas, it is the county seat of Dallas County and the biggest city in that county. Portions of the city also extend into the counties of Collin, Denton, Kaufman, and Rockwall. It is the ninth most populous city in the United States, according to the results of the 2020 census, and after Houston and San Antonio, it is the third largest city in the state of Texas. The city of Dallas, which can be found in the North Texas region, serves as the major centre of the biggest metropolitan area in the southern United States. It is also the largest inland metropolitan area in the United States that does not have any navigable connection to the sea.
The initial development of the cities of Dallas and nearby Fort Worth was spurred on by the construction of major railroad lines that passed through the area. These lines provided access to cotton, cattle, and later oil that was located in North and East Texas. Dallas's position as a transportation centre was bolstered by the development of the Interstate Highway System, which resulted in four main interstate routes converging in the city and a fifth interstate highway looping around it. The subsequent development of Dallas as a powerful industrial and financial centre, as well as a major inland port, was made possible by the convergence of major railroad lines, the construction of interstate highways, and the establishment of Dallas/Fort Worth International Airport, one of the largest and busiest airports in the world. Consequently, Dallas became a major inland port. In addition, Dallas offers DART, which stands for the Dallas Area Rapid Transit, which is a system of various coloured rail lines that run all throughout the Metroplex.
Its multifaceted economy is led by military, financial services, information technology, telecommunications, and transportation as its primary contributors. The Dallas–Fort Worth metroplex is home to 23 Fortune 500 companies, making it the second most populous region in Texas and the fourth most populous region in the United States. Eleven of these companies can be found within the boundaries of the city of Dallas. Greater than 41 colleges and universities can be found inside its metropolitan region, making it the metropolitan area in Texas with the highest concentration of higher education institutions. The city is home to people of a diverse range of racial, religious, and sexual orientations, making it one of the most inclusive communities in the United States. In 2018, the website WalletHub ranked Dallas as the fifth most diverse city in the United States.