An intermontaine valley at approximately 4,850 feet (1,480 m) elevation, Sierra Valley is surrounded by mountains ranging in elevation from 6,000 to 8,000 feet (2,400 m). The huge valley, 120,000 acres (490 km2),[contradictory] is a down-faulted basin, formerly a lake of similar geologic origin to Lake Tahoe to the south, now filled with sediment up to two thousand feet thick. The former Lake has the suggested name of Lake Beckwourth and existed until approximately 10,000 years ago.<ref> https://www.sierracountyhistory.org/wp-content/uploads/2015/02/Sierran-Winter-2015.pdf <ref>Average annual rainfall is less than twenty inches, most falling as snow. The valley floor has a grassland and sagebrush ecosystem and is the site of extensive freshwater marshes filled with cattails, bulrushes and alkaline flats that drain into the Middle Fork Feather River. Many species of wildlife make their permanent home in the valley, and a great number of migratory bird species stop over in the fall and nest in the valley in the spring. The valley also has thermal activity, with Marble Hot Springs located in the north central valley floor.
Sierra Valley is an agricultural and livestock region. Tourism also contributes to the local economy.
Entrance from the west is through Yuba Pass on State Route 49. Entrance from the east is through Beckwourth Pass, the lowest mountain pass on the crest of the Sierra Nevada, on State Route 70. State Route 89 skirts the southern end of the valley. State Route 49, the Gold Rush trail, terminates at State Route 70 in Vinton, and the latter highway then terminates at Hallelujah Junction on U.S. Route 395 after passing through Chilcoot.
A Biological Baseline Study of Sierra Valley Marsh, California 1976. Dept. of Biology, SFSU. NSF SOS grant SMI-76-08071. This was a student originated study funded by the National Science Foundation to assess biological resources of the high-altitude freshwater marsh in Sierra Valley. https://archive.org/details/SierraValleyStudy/page/n23
- U.S. Geological Survey Geographic Names Information System: Sierra Valley
- Plumas County Visitors Bureau
- Plumas National forest
- Tahoe National forest