Harlingen is a city in Cameron County. It is the second-largest city in the county, the fourth-largest in the Rio Grande Valley, and a principal city of the Brownsville-Harlingen metropolitan area. It is strategically located at the junction of US 77 and US 83; thus, Harlingen easily developed as a center for industrial, shipping, and distribution. It was founded in 1904 when Lon Hill visualized the Arroyo Colorado as a commercial waterway; he named the town he founded on the north bank after a city in Holland. That same year, a post office was established and six years later, Harlingen was incorporated. Vegetables and cotton were the primary cash crops in the area. The installation of the WWII military base sparked its population from 23,000 to 41,000 by 1960. The city became a busy industrial airpark where bombers used to land. As of 2000, its population was 57,564.