Dallas is a city in the U.S. state of Texas and the largest city in and seat of Dallas County, with portions extending into Collin, Denton, Kaufman and Rockwall counties. With an estimated 2019 population of 1,343,573, it is the ninth most-populous city in the U.S. and the third-largest in Texas after Houston and San Antonio. Located in North Texas, the city of Dallas is the main core of the largest metropolitan area in the Southern United States and the largest inland metropolitan area in the U.S. that lacks any navigable link to the sea. It is the most populous city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the country at 7.5 million people.
Dallas and nearby Fort Worth were initially developed due to the construction of major railroad lines through the area allowing access to cotton, cattle and later oil in North and East Texas. The construction of the Interstate Highway System reinforced Dallas's prominence as a transportation hub, with four major interstate highways converging in the city and a fifth interstate loop around it.