Warm Lake is a 640-acre (260 ha) lake in Idaho, United States. It is located 26 miles (42 km) east of Cascade in Valley County, at 5,298 feet (1,615 m) above sea level. It is the largest natural lake in Boise National Forest.
The lake's abundance of wildlife makes it very popular for camping, fishing, and hunting. Large mammals present in the area include moose, mule deer, black bear, and elk. Large birds present in the area include bald eagles and osprey. The lake contains rainbow, brook, lake, and bull trout as well as mountain whitefish and Kokanee salmon.