Middle Popo Agie River

Middle Popo Agie River
The Middle Popo Agie River seen from Main Street in Lander, Wyoming.
The Flow of the Middle Popo Agie from source to confluence.
Etymologyword po-PO-shuh, meaning "Head River" or possibly "Gurgling River"
Location
CountryUnited States
StateWyoming
CityLander, Wyoming
Physical characteristics
SourceSweetwater Gap
  locationWind River Range, Fremont County
  elevation12,000 ft (3,700 m)
MouthPopo Agie River
  location
Fort McGraw
  coordinates
42°51′14″N 108°42′00″W / 42.8540°N 108.6999°W / 42.8540; -108.6999
  elevation
5,000 ft (1,500 m)
Length54 mi (87 km)
Basin features
Tributaries 
  leftBaldwin Creek, Beason Creek
  rightSawmill Creek, Red Canyon Creek,Roaring Fork Creek

The Middle Popo Agie River (also known as the Middle Fork Popo Agie River} is a river in Fremont County, Wyoming, United States. The river is 54 miles (87 km) long. The river is sometimes referred to as simply the 'Middle Fork'. The river is part of the Popo Agie Watershed and from its headwaters in the Wind River Range until it joins with the North Popo Agie River to form the Popo Agie River in the Wind River Basin, the river and its tributaries irrigate roughly 11,503 acres.

The river is notable for passing underground through a sinkhole in Sinks Canyon State Park, only to emerge several hundred yards downstream at "the rise." The ground distance is not far, but tests with dye have shown it takes the water many hours to flow through the underground passage.