Summit Valley is a

valley A valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over ...

along

SR 138 Highway 138 may refer to: Canada * Ontario Highway 138 * Prince Edward Island Route 138 * Quebec Route 138 Costa Rica * National Route 138 (Costa Rica), National Route 138 India * National Highway 138 (India) Japan * Japan National Route ...

in the

San Bernardino Mountains The San Bernardino Mountains are a high and rugged mountain range in Southern California in the United States. Situated north and northeast of San Bernardino and spanning two California counties, the range tops out at at San Gorgonio Mountain ...

, east of

Cajon Pass Cajon Pass (; Spanish: ''Puerto del Cajón'' or ''Paso del Cajón'') is a mountain pass between the San Bernardino Mountains to the east and the San Gabriel Mountains to the west in Southern California. Created by the movements of the San Andr ...

within

San Bernardino County, California San Bernardino County ( ), officially the County of San Bernardino and sometimes abbreviated as S.B. County, is a County (United States), county located in the Southern California, southern portion of the U.S. state of California, and is locat ...

. Its mouth lies at an elevation of west of the source of the

Mojave River The Mojave River is an intermittent river in the eastern San Bernardino Mountains and the Mojave Desert in San Bernardino County, California, United States. Most of its flow is underground, while its surface channels remain dry most of the ti ...

, at the

confluence In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main ...

of the

West Fork Mojave River West Fork Mojave River is a tributary stream of the Mojave River in the San Bernardino Mountains of San Bernardino County, California. Its mouth lies at an elevation of at its confluence with Deep Creek, together the source of the Mojave River. ...

and Deep Creek. The West Fork Mohave River descends from

Silverwood Lake Silverwood Lake is a large reservoir (water), reservoir in San Bernardino County, California, United States, located on the West Fork Mojave River, a tributary of the Mojave River in the San Bernardino Mountains. It was created in as part of the ...

reservoir through the eastern part of Summit Valley to the confluence. The western half of Summit Valley narrows into what is called

Horsethief Canyon Horsethief Canyon, is a canyon comprising the upper part of the Summit Valley in San Bernardino County, California. Its head lies at at an elevation of 3,800 feet just east of the summit of Cajon Pass, and its mouth at an elevation of . Cali ...

, that reaches to the head of Summit Valley at , just east of the summit of Cajon Pass.

References

{{coord, 34, 20, 17, N, 117, 16, 12, W, display=title Valleys of San Bernardino County, California San Bernardino Mountains