About 1,900 miles · CO, NM, TX · source San Juan Mountains · mouth Gulf of Mexico near Brownsville
Rio Grande map
The Rio Grande flows about 1,900 miles from the San Juan Mountains of Colorado through New Mexico to the Gulf of Mexico, forming about 1,250 miles of the Texas–Mexico border.
Where the Rio Grande is
The river begins in the San Juan Mountains of southwestern Colorado at about 12,000 ft, crosses the San Luis Valley past Alamosa, and enters New Mexico through the Rio Grande Gorge near Taos. It runs down the centre of New Mexico through Albuquerque and Las Cruces, reaches El Paso, Texas, and from there is the international boundary all the way to the Gulf of Mexico between Brownsville and Matamoros. At about 1,900 miles it is the fourth-longest river in the US. In Mexico it is the Río Bravo del Norte.
States along the river
- Colorado — about 175 miles, the headwaters and the San Luis Valley.
- New Mexico — about 470 miles, from the gorge to the Texas line; Elephant Butte Reservoir stores the state's share.
- Texas — about 1,250 miles as the border with the Mexican states of Chihuahua, Coahuila, Nuevo León and Tamaulipas.
Key measurements
- Length: about 1,900 miles (often quoted as 1,896).
- Main tributaries: the Rio Conchos, from Mexico, which supplies most of the flow below Presidio; the Pecos, which joins above Amistad Reservoir; the Devils River.
- Reservoirs: Elephant Butte (New Mexico), Amistad (near Del Rio) and Falcon (near Laredo), the last two shared with Mexico.
- In dry years the river runs empty for long stretches below El Paso; in some years it has failed to reach the Gulf.
Cities on the river
Albuquerque is the largest city on the river. El Paso and Ciudad Juárez face each other where the river becomes the border. Downstream are Presidio, Del Rio, Eagle Pass, Laredo (the busiest inland port on the border), McAllen and Brownsville. Santa Fe is about 20 miles east of the river.
How the river shaped the map
The 1848 Treaty of Guadalupe Hidalgo fixed the Rio Grande as the Texas–Mexico boundary, ending the dispute over whether Texas stopped at the Nueces. Because the channel kept shifting, the two countries had to settle stranded parcels; the Chamizal agreement of 1963 re-drew the line at El Paso. The river also gives Big Bend National Park its 118-mile southern edge, where the river turns sharply northeast. West of El Paso the border leaves the river and follows straight survey lines to the Pacific.
Related maps
- Gulf of Mexico — where the river ends.
- Rocky Mountains — the source range.
- US deserts — the Chihuahuan Desert lies along the middle river.
- Longest US rivers · Southwest states · All geography maps.