- Soap Lake is a town of 1,600 people (2018) in Columbia River Plateau of Washington State. The lake’s naturally occurring foam gives its water a soapy appearance, and the lake’s mineral-rich waters have a slick, soapy feel.
- Columbia River Plateau (en.wikivoyage.org)
The Columbia River Plateau, sometimes called the Columbia River Basin, is a broad plateau in Washington State where the Columbia River rolls its way between the Cascade Mountains and the Rocky Mountain foothills. Extensive infrastructure projects along the river have transformed this semi-arid sagebrush steppe into a literal powerhouse of energy and agriculture.