Soap Lake

Soap Lake, southernmost in a string of lakes in the Grand Coulee valley, central Washington state, U.S. Volcanic in origin, its water is rich in minerals and salts and is regarded as having medicinal properties. The lake derives its name from the frothy white suds that appear along its shores, created by the action of the wind on the water’s high concentrations of carbonates. The city of Soap Lake, on its shores, was popular as a health resort in the early and mid-20th century.