Texas's 20th congressional district of the United States House of Representatives includes the western half of San Antonio and Bexar County in Texas. The district is heavily Latino/Hispanic, as is the surrounding area. Charlie Gonzalez, who represented the district from 1999 to 2013 after succeeding his father, Henry B. González, did not seek re-election in the 2012 United States House of Representatives elections. State representative Joaquin Castro, the Democratic nominee to replace Gonzalez, defeated David Rosa, the Republican nominee, in the race for Texas's 20th district on November 6, 2012. His term began on January 3, 2013.

Bexar County is a county in the U.S. state of Texas. It is in South Texas and its county seat is San Antonio.