Spirit Lake, Alpine lake in Skamania County, Washington, United States.

Spirit Lake lies north of Mount St. Helens at about 1,040 meters, its deep blue water divided into two long arms by a broad tongue of light gray debris reaching from the right shore. The surface is mostly smooth, with scattered small floating patches and faint reflections on the left arm, and steep gray-brown slopes border the water.

Before 1980, six camps lined the shore, including facilities run by youth organizations and scouting groups. The volcano erupted in May 1980, burying these sites under tons of debris and reshaping the entire basin.

Settlers took the name from Native American accounts of haunting spirits at the lake: mists shaped themselves into trees and animals, foretelling doom and good fortune in the afterlife, and anyone who saw the apparitions died within a week. A post office named Spirit Lake was later renamed Lange in 1910 after its postmaster.

A tunnel at the outlet, finished in 1985, channels overflow through an underground passage more than 2.5 kilometers long. Visitors can view the body of water from several overlooks in the area, though direct access remains limited.

During the 1980 eruption, a landslide pushed the water aside and sent waves up to 260 meters above the normal surface. About 430 million cubic meters of material slid into the basin, changing the depth and shape completely.