Shaped like the ace of clubs, drains a chain of ponds in the center of a skiing area. A small picnic area in the green bowl surrounding the lake, a natural basin, has tables, stoves, and running water. Trails radiate to great spires of rock affording excellent viewpoints. A bronze plaque, set in a large boulder, has a bas-relief bust of the late Stephen T. Mather, who laid the foundation of the National Park Service.

The lake is fed by springs and snow melt, and is ice-free only during the summer. This Native American name means grassy lake.