Terwilliger Valley is a basin in

Riverside County, California Riverside County is a County (United States), county located in the Southern California, southern portion of the U.S. state of California. As of the 2020 United States Census, 2020 census, its population was 2,418,185, making it the fourth-most ...

. The valley lies at an elevation of .

Geography

It is 2 miles southeast of Anza Valley, however unlike Terwilliger Valley, water from the Anza Valley eventually drains into the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

. Terwilliger Valley is drained by Coyote Creek, which leads to Coyote Canyon in

Anza-Borrego Desert State Park Anza-Borrego Desert State Park (, ''Help:Pronunciation respelling key, AN-zə bə-RAY-goh'') is a California State Park located within the Colorado Desert of Southern California, United States. Created in 1932, the park takes its name from 18th ...

, a popular destination for desert wildflower viewing. The basin is immediately west of the

San Jacinto Fault The San Jacinto Fault Zone (SJFZ) is a major strike-slip fault zone that runs through San Bernardino, Riverside, San Diego, and Imperial Counties in Southern California. The SJFZ is a component of the larger San Andreas transform system and ...

. It was the site of a 6.0 earthquake in 1937.San Jacinto Fault (Terwilliger Valley) Earthquake
from scedc.caltech.edu accessed February 5, 2025.

References

{{coord, 33.5000301, -116.6383518, display=title Valleys of Riverside County, California