Texas's 28th congressional district of the United States House of Representatives covers a strip in deep south Texas starting in the eastern outskirts of San Antonio, and ending at the U.S.–Mexico border.

TX-28 includes The Alamo, a historic monument in what is now downtown San Antonio that plays a central role in Texas' identity.

On June 28, 2006, the U.S. Supreme Court declared that the Texas legislature's redistricting plan violated the Voting Rights Act in the case of Texas's 23rd congressional district.

On election day in November, these five districts had open primaries, or a "jungle primary"; any candidate that receives more than 50% of the vote wins the seat.

Otherwise, a runoff election in December will decide the seat.