Harlingen Air Force Base, originally known as Harlingen Army Air Field, site of Harlingen Army Gunnery School, was located three miles northwest of Harlingen in Cameron County. The first military personnel arrived in December 1941. The field began operations as a gunnery school specializing in training for high and low aerial gunnery and in B-24 transition training on August 3, 1942, under command of Col. John. R. Morgan. The field, described as the "Paradise of the Eastern Flying Training Command," had an important part in cultivating American-Mexican relations. Harlingen Army Air Field was closed in February 1946 and reactivated as Harlingen Air Force Base in April 1952 as a consequence of the Korean War. It was expanded from 960 acres to 1,400 acres and served primarily as a navigator-training school. The reopening was a major influence on the growth of Harlingen. The base was again closed in 1962; by 1963 the phase-out was completed, and the facilities were converted to civilian use, including use as Rio Grande Valley International Airport.