Western Snake River Plain- Treasure Valley General Description
The Treasure Valley, which includes the lower Boise River basin and extends south to the Snake River is located within the northwest-trending topographic depression known as the western Snake River Plain. The western Snake River Plain is a relatively flat lowland separating Cretaceous-age granitic mountains of west-central Idaho from the granitic/volcanic Owhyee mountains in southwestern Idaho. The western Snake River Plain extends from about Twin Falls, Idaho northwestward to Vale, Oregon. The Snake River Plain is about 30 miles wide in the section containing the lower Boise River. The depression is believed to have been formed by crustal extension, beginning as early as 17 million years ago (Malde, 1991).

For geologic information on the Treasure Valley click on the following links:
Ada County
Canyon County
Elmore County
Gem County
Payette County
Snake River Plain Geology
Treasure Valley Geology

Original content compiled by Christian Petrich, Margie Wilkins, Tondee Clark, and Tony Morse.
Photo provided by Idaho Department of Water Resources
Adaptation for the Digital Atlas of Idaho by Ean Harker- design/html, Kyle Raverty- content, 11-2002.
Information supplied by the Idaho Department of Water Resources; 1301 North Orchard Street Boise, Idaho 83706 (208) 327-7900.