[2] Grays Lake lies within the Caribou Range of the Rocky Mountains in southeast Idaho, and is at the western edge of the Greater Yellowstone Ecosystem.
At the heart of the valley is a large, 22,000-acre (89 km2) shallow montane marsh, composed primarily of hardstem bulrush and cattail with scattered small ponds.
The area is significant for its high density of breeding sandhill cranes and as a reintroduction site for trumpeter swans.
The rich wet meadow edges of the marsh provide foraging and nesting habitat for a diversity of water birds each year.
Currently, the refuge's goals are to enhance natural ecosystem functions to support a diversity of water birds and other wildlife.