Texas's 12th congressional district in the United States House of Representatives is in the north portion of the state of Texas. As of 2017, the 12th district contained 806,551 people and had a median income of $67,703. It consists of the western half of Tarrant County, as well as most of Parker County. The district also contains Texas Christian University. Fragments of the Dallas–Fort Worth metroplex are included in the district. The district is currently represented by Republican Kay Granger, who was first elected in 1996.

Tarrant County is a county located in the U.S. state of Texas with a 2020 U.S. census population of 2,110,640, making it the third-most populous county in Texas and the 15th-most populous in the United States. Its county seat is Fort Worth. Tarrant County, one of 26 counties created out of the Peters Colony, was established in 1849 and organized the next year. It is named after Edward H. Tarrant, a lawyer, politician, and militia leader.