Starr County is located in the U.S. state of Texas. As of the 2020 census, its population was 65,920. Its county seat is Rio Grande City. The county was created in 1848. It is named for James Harper Starr, who served as secretary of the treasury of the Republic of Texas. Starr County comprises the Rio Grande City micropolitan statistical area, which also includes other small cities, which itself is part of the larger Rio Grande Valley region. It is directly northeast of the Mexican border.