Jackson Lake Dam, Gravity dam in Grand Teton National Park, US.

Jackson Lake Dam is a concrete gravity dam with earthen embankment wings at the outlet of Jackson Lake, where the Snake River begins its course. Its crest runs 4,920 feet (1,500 m) and stands 65 feet (20 m) high, holding the lake up to 30 feet above its natural level. The dam is owned and operated by the U.S. Bureau of Reclamation.

The dam was constructed between 1911 and 1916 by the Bureau of Reclamation, replacing an earlier log structure that collapsed at the natural lake outlet in 1910. This concrete replacement marked a turning point in regional water management infrastructure.

The dam functions as part of the Minidoka Project, supplying essential irrigation water to agricultural lands throughout the Snake River basin in Idaho.

The dam sits at the outlet of Jackson Lake in Grand Teton National Park, reached from the Moran entrance and the Grassy Lake Road area north of the park. The crest is 4,920 feet (1,500 m) long and 24 feet (7.3 m) wide, with earthen embankment wings at each end. Water levels vary between the minimum pool at 6,730 feet and the maximum at 6,769 feet, so the shoreline and mudflats change with drawdown.

When the dam raised the water, no attempt was made to clear standing timber from the shores, leaving a band of dead trees visible above the waterline. This vista, along with the mudflats exposed by drawdown, was later cited in successful arguments against reservoirs in Yellowstone National Park.