The Mancos River, formerly also El Rio de San Lazaro, is an 85.4-mile-long (137.4 km)[2] northeast tributary of the San Juan River. It flows from the confluence of West Mancos River and East Mancos River near Mancos, Colorado and joins the San Juan near Four Corners Monument in New Mexico.[1]
| Mancos River[1] | |
|---|---|
 Mancos River, San Juan River confluence (Four Corners) (Carrizo Mountains at southwest) | |
| Physical characteristics | |
| Source | |
| • location | Confluence of West Mancos River and East Mancos River |
| • coordinates | 37°21′30″N 108°15′12″W / 37.35833°N 108.25333°W |
| Mouth | |
• location | Confluence with San Juan |
• coordinates | 36°59′00″N 108°58′50″W / 36.98333°N 108.98056°W |
• elevation | 4,639 ft (1,414 m) |
| Basin features | |
| Progression | San Juan—Colorado |
The river was named after an incident during which a horse rider hurt his hand while crossing, the word Mancos being derived from Spanish meaning "one-armed".[3]