The Yampa River flows 250 miles (400 km) through northwestern Colorado, United States. Rising in the Rocky Mountains, it is a tributary of the Green River and a major part of the Colorado River system. The Yampa is one of the few free-flowing rivers in the western United States, with only a few small dams and diversions.
The name is derived from the Snake Indians word for the Perideridia plant, which has an edible root. John C. Frémont was among the first to record the name 'Yampah' in entries of his journal from 1843, as he found the plant was particularly abundant in the watershed.

Quelle: Wikipedia