Soap Lake is located in eastern Washington at the southern end of the Lower Grand Coulee. Carved by the erosive forces of cataclysmic floods, the lake paints a serene portrait across a landscape framed with rugged basalt cliffs and talus slopes. After thousands of years, groundwater leaching through hundreds of feet of basalt created the lake, which has a high concentration of sulfate, carbonate, bicarbonate, sodium, and chloride and a pH at or close to 10.0. Prior to the development of penicillin and sulfa drugs in the 1940s, Soap Lake became widely known for the healing quality of its waters, attracting thousands of visitors each summer, some of whom arrived on stretchers at the nearby train station.