he Teton River subbasin is one of three watersheds that comprise the Henrys Fork Basin. The Teton River drains an area of 806 square miles in Idaho and 327 square miles in Wyoming. The river originates from headwater streams in the Teton, Big Hole, and Snake River Mountain Ranges and flows more than 64 miles to where it discharges to the Henrys Fork River.
Teton Canyon contains the river for approximately 17 miles. In 1975, Teton Dam was completed at the lower end of the canyon to create a reservoir for irrigation water. In June 1976, when the reservoir behind the dam had almost filled, the earthen dam collapsed. More than 250,000 acre-feet of water and 4 million cubic yards of embankment material flowed through the breach in less than 6 hours. The portion of the river below the dam was extensively altered by the flood and by the mitigation and restoration work that followed. However, the quality of water in the Teton River subbasin is generally good.