Anza Valley, formerly known as the Hamilton Plains,[1] is a basin in Riverside County, California.

It lies at an elevation of 4,157 feet (1,267 m), west of the San Jacinto and Santa Rosa Mountains.

Anza Valley trends southwest from Bautista Canyon, west of Thomas Mountain to Terwilliger Valley, 2.8 miles west-southwest of Table Mountain and 12 miles south of Idyllwild.

[4] In the later 19th century, Anza Valley was named after its early pioneer settler, Jim Hamilton, an African American man who settled there after he lost his land in Butterfield Valley in a lawsuit over ownership of the Rancho Pauba in the early 1880s.

Hamilton Creek, originating east of Anza still bears his name.