Harlingen is a city in Cameron County in the central region of the Rio Grande Valley of the southern part of the U.S. state of Texas, about 30 miles (48 km) from the coast of the Gulf of Mexico. The city covers more than 40 square miles (104 km2) and is the second-largest city in Cameron County, as well as the fourth-largest in the Rio Grande Valley. As of the 2020 census, the city had a population of 71,892.

Cameron County, officially the County of Cameron, is the southernmost county in the U.S. state of Texas. As of the 2020 census, its population was 421,017. Its county seat is Brownsville.