Fall River (Henrys Fork tributary)

Fall River
Fall River, Yellowstone National Park, 1964
Location of the mouth of the Fall River in Idaho
Fall River (Henrys Fork tributary) (the United States)
Location
CountryUnited States
StateWyoming, Idaho
CountiesTeton County, Wyoming, Fremont County, Idaho
Physical characteristics
Source 
  locationsouthwest of Lewis Lake, Teton County, Wyoming
  coordinates44°14′51″N 110°45′43″W / 44.24750°N 110.76194°W / 44.24750; -110.76194
  elevation8,872 ft (2,704 m)
MouthHenrys Fork
  location
northeast of St. Anthony, Fremont County, Idaho
  coordinates
44°01′07″N 111°34′52″W / 44.01861°N 111.58111°W / 44.01861; -111.58111
  elevation
5,046 ft (1,538 m)
Length64 mi (103 km)

Fall River rises on the Madison and Pitchstone Plateaus in the southwest corner of Yellowstone National Park, Wyoming and flows approximately 64 miles (103 km) to its confluence with the Henrys Fork of the Snake River near Ashton, Idaho. Historically, the river was referred to as the Middle Fork of the Snake River or as Fall River or the Falls River by trappers and prospectors as early as the 1830s. It was officially named the Falls River by the 1872 Hayden Geological Survey, but was always called Fall River by the locals and so the U.S. Board on Geographic Names changed the official name to Fall River in 1997 at the request of Idaho authorities. The river is home to numerous waterfalls and cascades in its upper reaches.