El Paso County is the westernmost county in the U.S. state of Texas. As of the 2020 census, its population was 865,657, making it the tenth-most populous county in Texas. Its county seat is the city of El Paso, the sixth-most populous city in Texas and the 22nd-most populous city in the United States.El Paso County is the westernmost county in the U.S. state of Texas. As of the 2020 census, its population was 865,657, making it the tenth-most populous county in Texas. Its county seat is the city of El Paso, the sixth-most populous city in Texas and the 22nd-most populous city in the United States. Source: Wikipedia