Temecula Valley is a graben rift valley in western Riverside County, California. Temecula Valley is one of the graben valleys making up the Elsinore Trough, created by the Elsinore Fault Zone. It lies between the Wildomar Fault on the east, at the foot of the Temescal Mountains and of the Temecula Basin and the Willard Fault on the west, at the foot of the Santa Ana Mountains. Temecula Valley lies northwest of Temecula Creek, and its head (33°36′46″N 117°17′33″W / 33.61278°N 117.29250°W) is south of the Elsinore Valley, from which it is divided by a low rise between the Temescal and Santa Ana Mountains.