Mushroom Lake is located on the eastern side of the Sawtooth National Wilderness Area, Custer County, Idaho, USA.  The lake sits at 8,560 feet (2,609m) above sea-level and is a 6 mile (9.7km) hike from the nearest 4-wheel drive road running up Hell Roaring Canyon.  The entire hike is on a well maintained hiking trail except for the last mile.  The total elevation change of the hike is 1,340 feet (408m).

This image was taken on October 28, 2011 from the lake's northern shoreline.  Mushroom Lake is approximately 650 feet (198m) long and 650 feet (198m) wide and has a shoreline distance of about 0.5 miles (0.8km).  In this image the lake has a thin layer of ice on it.

The best time for visiting in summer weather is August through October.