Flaming Gorge Reservoir is in Wyoming (and partially in Utah), created by the construction of the Flaming Gorge Dam across the Green River. It was built between 1958 and 1964 and created a massive body of fresh water. The reservoir stores 3,788,900 acre feet(4.6735×109 m3) of water, has a length of 91 miles (145 km) and a shoreline of 375 miles (600 km). It's situated 6040 ft (1840 m) above sea level and has a maximum depth of 436 ft (133 m).
As you would expect from such a grand body of fresh water, there are plenty of outdoor activities in which you can partake, including boating, fishing, water-skiing, wind-surfing, hiking, camping and backpacking. In the winter there is cross-country skiing and snowmobiling. There's lots of wildlife in the area, so keep your eyes open for eagles or osprey.
(Flaming Gorge Dam)