Harlingen is a city in Cameron County, Texas. It is located in the central region of the Rio Grande Valley, 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 sixth-largest in the Rio Grande Valley. As of the 2020 census, the city had a population of 71,892.