RIO GRANDE

RIO GRANDE, a North American river, thirteen hundred miles of which form the boundary separating the United States and Mexico. It is the fifth longest river in North America. It rises in the San Juan Mountains in southwestern Colorado and flows generally southward through New Mexico until it reaches El Paso, TEXAS. It then flows generally to the southeast until it empties into the Gulf of Mexico at Brownsville, Texas, and Matamoros, Mexico.

After the LOUISIANA PURCHASE, American expansionists claimed the Rio Grande as the southern and western border of the territory covered by that purchase, but Spain successfully insisted on the Sabine River as the border. After Mexican independence from Spain in 1821, numerous American colonies sprang up in Texas. Still, dispute over the Texas-Mexican border was one of the main causes of the Texas Revolution in 1835–1836.

The Texas Republic maintained that the Rio Grande constituted its southern and western boundaries. The United States inherited those claims with the annexation of Texas in 1845, but Mexico's unwillingness to accept the river as the boundary was an immediate cause of the MEXICAN-AMERICAN WAR. The Treaty of Guadalupe Hidalgo, which ended the war, recognized the river as an international border.

The Rio Grande is not important as a trade route, but its waters have long been important for irrigation in the arid SOUTHWEST. In prehistoric times, the Pueblo of New Mexico built elaborate irrigation systems. In modern times, irrigation water from the Rio Grande supports the commercially important citrus and truck farm regions in the Rio Grande Valley in both Texas and Mexico. Cooperation between the two countries has resulted in various irrigation and flood-control projects, the most spectacular being the vast Amistad Dam.

BIBLIOGRAPHY

Francaviglia, Richard, and Douglas W. Richmond, eds. Dueling Eagles: Reinterpreting the U.S.-Mexican War, 1846–1848. Fort Worth: Texas Christian University Press, 2000.

Kelley, Pat. River of Lost Dreams: Navigation on the Rio Grande. Lincoln: University of Nebraska Press, 1986.

Rivera, José, A. Acequia Culture: Water, Land, and Community in the Southwest. Albuquerque: University of New Mexico Press, 1998.