Teton River, ID

The Teton River is a tributary of Henrys Fork of the Snake River, approximately 60 mi (97 km) long, in southeastern Idaho in the United States. It drains through the Teton Valley along the west side of the Teton Range along the Idaho-Wyoming border at the eastern end of the Snake River Plain. Its location along the western flank of the Tetons provides the river with more rainfall than many other rivers of the region.

The Teton River is formed near Victor in Teton County, Idaho, near the Wyoming state line, by the convergence of several small creeks that descend from surrounding mountains. Several of these creeks, including Teton Creek and Darby Creek, descend from the western flank of the Tetons. Trail Creek descends from the Caribou-Targhee National Forest in Idaho, meeting the other creeks from the south. The river flows north in a slow meandering course through a broad flat valley called the Teton Basin (formerly known as "Pierre's Hole"), flanked by the Teton Range to the east and the Big Hole Mountains to the west. Much of the river's upper course in the Teton Basin is surrounded by extensive wetlands.

After emerging from the north end of the Teton Basin, the Teton River enters the nearly inaccessible Teton Canyon, approximately 25 mi (40 km) long, along the Teton-Fremont county line. There it is joined by Badger Creek and Bitch Creek from the east, then turns west, and is joined by Canyon Creek from the south. After passing through the failed Teton Dam site, just north of Teton, the Teton River bifurcates into two distributaries, called the South Fork Teton River (also called the South Teton River) and the North Fork Teton River (also called the Teton River). The South Teton River travels generally south west until it joins Henrys Fork west of Rexburg at the southwest end of a large inland delta region on the Henrys Fork, essentially merging with the delta from the east as one of its channels. The Teton River itself (North Fork Teton) continues to travel west, where it joins the Henrys Fork at Warm Slough.