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.
