|States||Texas, New Mexico|
|- location||29 mi (47 km) north of Pecos, New Mexico|
|- elevation||11,759 ft (3,584 m)|
|- location||Seminole Canyon, Val Verde County, 37 mi (60 km) northwest of Del Rio, Texas|
|- elevation||1,115 ft (340 m)|
|Length||926 mi (1,490 km) |
|Basin||44,402 sq mi (115,001 km2) |
|Discharge||for IBWC station 08-4474.10 near Langtry, Texas|
|- average||265 cu ft/s (8 m3/s) |
|- max||152,910 cu ft/s (4,330 m3/s)|
|- min||42 cu ft/s (1 m3/s)|
Map of the Rio Grande watershed, showing the Pecos River flowing through east New Mexico and west Texas, joining the Rio Grande near Del Rio.
The headwaters of the Pecos River are located north of Pecos, New Mexico, United States, at an elevation of over 12,000 feet on the western slope of the Sangre de Cristo mountain range in Mora County. The river flows for 926 miles (1,490 km) through the eastern portion of that state and neighboring Texas before it empties into the Rio Grande near Del Rio. The river's drainage basin is approximately 44,300 square miles (115,000 km2) in size.
There are multiple dams along the Pecos River. Santa Rosa Lake is 117 miles/188 kM east of Albuquerque. Sumner Lake, formed by the 1939 Sumner Dam, is located between Santa Rosa and Fort Sumner, NM. Two dams are located north of Carlsbad, New Mexico, at Avalon Dam and Brantley Dam, to help irrigate about 25,000 acres (10,000 ha) as part of the Carlsbad reclamation project (established in 1906). Texas has also dammed the river at the Red Bluff Dam in the western part of that state to form the Red Bluff Reservoir. The portion of the reservoir that extends into New Mexico forms the lowest point in that state.
New Mexico and Texas disputed water rights to the river until the federal government settled the dispute in 1949 with the Pecos River Compact. The Pecos River Settlement Agreement was signed between New Mexico and Texas in 2003.
Wild and Scenic River 
On June 6, 1990, 20.5 miles (33 km) of the Pecos River—from its headwaters to the townsite of Tererro—received National Wild and Scenic River designation. It includes 13.5 miles (22 km) designated "wild" and 7 miles (11 km) designated "recreational."
Pecos River between Terrerro and Pecos, New Mexico
The Pecos River flowing south of Grandfalls, Texas
Pecos River near the Rio Grande
Pecos River Flume 
The Flume is a modern aqueduct carrying irrigation water over the Pecos River. Construction took place from 1889 to 1890 and was part of the Pecos River Reclamation Project. It was originally constructed of wood and spanned 145 feet (44 m). It carried water at a depth of 8 feet (2.4 m). In 1902, a flood destroyed the Flume and it was subsequently rebuilt using concrete. In 1902, it was identified as the largest concrete aqueduct in the world.
The Flume and its surrounding area have been reclaimed by the city of Carlsbad and has been transformed into a tourist attraction with park improvements along the river and spot lights to give a spectacular nightly view.
See also 
- List of longest rivers of the United States (by main stem)
- List of tributaries of the Rio Grande
- List of rivers of New Mexico
- List of rivers of Texas
- U.S. Geological Survey Geographic Names Information System: Pecos River
- Largest Rivers of the United States, USGS
- "Water Bulletin Number 75: Flow of the Rio Grande and Related Data; From Elephant Butte Dam, New Mexico to the Gulf of Mexico". International Boundary and Water Commission. 2005. Retrieved 17 July 2010.
- Santa Rosa Lake
- Sumner Lake
- Bright, William (2004). Native American placenames of the United States. University of Oklahoma Press. p. 375. ISBN 978-0-8061-3598-4. Retrieved 11 April 2011.
- Pecos River Compact
- Pecos River Settlement Agreement
- Pecos Wild and Scenic River, New Mexico - National Wild and Scenic Rivers System
- Phil T. Archuletta; Sharyl S. Holden (June 2003). Traveling New Mexico: a guide to the historical and state park markers. Sunstone Press. pp. 116–. ISBN 978-0-86534-400-6. Retrieved 3 December 2011.
- American Concrete Institute (2002). Concrete international. Design & construction. The Institute. Retrieved 3 December 2011.