Impasse Lake is located on the eastern side of the Sawtooth National Wilderness Area, Custer County, Idaho, USA.  The lake sits at 8,950 feet (2,728m) above sea-level and is a 7 mile (11.3km) 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 2 miles.  The total elevation change of the hike is 1,730 feet (527m).

This image was taken on October 28, 2011 from the lake's northeast shoreline.  Impasse Lake is approximately 615 feet (187m) long and 340 feet (104m) wide and has a shoreline distance of about 1,600 feet (488m).  The surface of the lake is frozen and shows patterns of cracking.  10,211 foot (3112m) Payette Peak can be seen directly west.

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