It stretches from western San Antonio to El Paso, encompassing numerous county seats and towns of regional economic importance.

Campaigning is difficult due to its size and disparate influences; the population density is one of the lowest in any congressional district.

Largely because of his popularity in San Antonio, he did not face a credible challenger until 2002, when the former Democratic Texas Secretary of State, Henry Cuellar, came within 2 points of unseating him.

Several heavily Republican suburbs in the Texas Hill Country north of San Antonio were shifted into the 23rd district, all but ensuring Bonilla of a seventh term.

[6] Bexar (part), Brewster, Crane, Crockett, Culberson, Dimmit, Edwards, El Paso (part), Frio, Hudspeth, Jeff Davis, Kinney, La Salle, Loving, Maverick, Medina, Pecos, Presidio, Reagan, Reeves, Schleicher, Sutton, Terrell, Upton, Uvalde, Val Verde, Ward, Winkler, and Zavala[11]