The Border Patrol had its start in the Rio Grande Valley area in 1921 with four officers assigned to Hidalgo, two to Brownsville and two to Rio Grande City, Texas. In 1923, additional officers were assigned to Alice, Harlingen, Kingsville and Mission. From its inception and until about 1938 Sector Headquarters was located at Brownsville, Texas. In 1935, consideration was given to moving Sector Headquarters to a more centralized location and Harlingen, Weslaco, McAllen and Edinburg were contemplated as prime locations. The City of McAllen made the best offer, which consisted of a lease purchase agreement on a building and five acres of land with the lease money to be applied to the purchase price. In 1938, Sector Headquarters was moved to its present location McAllen, Texas, and in 1941, the land and buildings were purchased from the City of McAllen for $5,000. The original building was removed and a new building constructed upon the same site in 1972. On March 22, 2005, the McAllen Sector name was officially changed to Rio Grande Valley Sector.

From McAllen Sector's original staff of 8 officers, Sector's manpower gradually increased until 1936, bringing the total to about 40 officers. Further increases came during 1940 through June 1954, with peak strength fluctuating between 100 and 115 officers. During the first half of 1954, station manpower was as follows: Mission 4, Edinburg 4, Harlingen 6 to 8, San Benito 4, Raymondville 4, Weslaco 4, Roma 2 to 4, Falfurrias 12, McAllen 28, Kingsville 18, Mercedes 4 and Sector Headquarters 8 to 10.

On January 30, 2006, Rio Grande Valley Sector relocates to its new state of the art building now located at 4400 South Expressway 281 in Edinburg, Texas. Construction began in August of 2005 and was completed in January of 2006. Sundt Construction Company was contracted to build the new sector headquarters at a cost of $22 million. The U.S. Army Corp of Engineers from Galveston, Texas oversaw the project. The three primary buildings at the site are a 32,229 square foot two-story management building, a 15,531 square foot mission support building and a 23,814 square foot enforcement building. HDR Architecture from Dallas, Texas designed the new buildings. Phase 2 and 3 call for additional buildings to be constructed which will consist of a 6,600 square foot law enforcement communications building for an estimated 30 employees, a 6,438 square foot asset forfeiture building for an estimated 4 employees, a 11,800 square foot training building for an estimated 40 employees, a 94,600 square foot supply warehouse, maintenance and electronic building for an estimated 45 employees, and a 3,574 square foot canine facility for an estimated 4 employees.

The Rio Grande Valley Sector now has 9 stations, 2 checkpoints, air operations and an intelligence office. RGV patrols over 320 river miles, 250 coastal miles and encompass 19 counties equating to over 17,000 square miles.