Jackson, Moraine-dammed lake in Grand Teton National Park, Wyoming, US

Jackson Lake lies in the northern part of Grand Teton National Park at 2,064 m (6,772 ft) elevation. The natural lake was raised about 10 m (33 ft) by the Jackson Lake Dam, first built in 1911, enlarged in 1916 and rebuilt by 1989. It is fed by the Snake River from the north and drains at the dam. The lake is up to 24 km (15 mi) long, 11 km (7 mi) wide and 134 m (438 ft) deep, with over 15 islands including Elk Island and Donoho Point.

Jackson Lake is a remnant of glacial gouging by the Teton Range and the Yellowstone Plateau. The natural lake was enlarged by the Jackson Lake Dam, first built in 1911, enlarged in 1916 and rebuilt by 1989. Under water rights predating Grand Teton National Park, the top 33 ft (10 m) of the lake is used for irrigation by Idaho farmers as part of the Minidoka Project.

The lake lies within Grand Teton National Park, and its eastern shore holds the marinas and lodges that visitors use today: Leeks Marina, Colter Bay Village, Jackson Lake Lodge and Signal Mountain Lodge. All except Jackson Lake Lodge have boat ramps. The western shore has only hiking trails and a few primitive campsites.

Visitors can access the lake at several points along the shore, where camping areas and facilities are scattered throughout the park. The season for most outdoor activities runs from spring through fall, when weather and facilities are generally available.

The top 33 ft (10 m) of the lake is drawn for irrigation by Idaho farmers, under water rights enacted before Grand Teton National Park existed. The dam that makes this possible was first built in 1911, enlarged in 1916 and rebuilt by 1989. The lake holds over 15 islands, the largest being Elk Island.