Jackson Lake is in Grand Teton National Park in northwestern Wyoming.[3] This natural lake was enlarged by the construction of the Jackson Lake Dam, which was originally built in 1911, enlarged in 1916 and rebuilt by 1989.[4] The top 33 ft (10 m) of the lake is utilized by farmers in Idaho for irrigation purposes. The lake is the remnant of large glacial gouging from the neighboring Teton Range to the west and the Yellowstone Plateau to the north.[5] The lake is primarily fed by the Snake River, which flows in from the north, and empties at Jackson Lake Dam. Jackson Lake is one of the largest high altitude lakes in the United States, at an elevation of 6,772 ft (2,064 m) above sea level. The lake is up to 15 mi (24 km) long, 7 mi (11 km) wide and 438 ft (134 m) deep. The water of the lake averages below 60 °F (16 °C), even during the summer.