Jenny Lake, Glacial lake in Grand Teton National Park, United States.

Jenny Lake is a glacial lake in Grand Teton National Park with clear water reflecting sharp granite peaks. The water extends across a broad area and reaches considerable depths, surrounded by steep mountainsides and open shoreline.

The lake was named in 1872 during the Hayden Expedition, a geological survey mission exploring the Teton Range. The name honors Jenny Leigh, wife of a guide who assisted the expedition.

The lake carries the name of Jenny Leigh, a Shoshone woman married to the Englishman Richard "Beaver Dick" Leigh; she assisted the 1872 geological expedition and died with their six children of smallpox in 1876. Her name was given to the water and to the surrounding landmarks.

The 11.4 km Jenny Lake Trail circles the lake with about 210 m of elevation gain, an easy loop until the route enters Cascade Canyon, where the climb steepens. Jenny and Jackson are the only lakes in the park where motorboats are allowed, and scenic boat tours run on both. A 2005 water-quality study found the park's lakes free of air and water pollution.

Jenny Lake and Jackson Lake are the only two lakes in Grand Teton National Park where motorboats are allowed. A 2005 water-quality study found all park lakes still free of air- and water-borne pollution. The lake's outlet feeds a boat shuttle across to Cascade Canyon.