Jackson Lake Dam is a concrete and earth-fill dam at the outlet of Jackson Lake in northwestern Wyoming, USA. The lake and dam are situated within Grand Teton National Park in Teton County. The Snake River emerges from the dam and flows about 800 miles (1,287 km) through Wyoming, Idaho, Oregon, and Washington to its mouth on the Columbia River in eastern Washington. The chief purpose of the dam is to provide water storage for irrigation in the Snake River basin in the state of Idaho as part of the Minidoka Project.