Temecula Valley, Rift valley in Riverside County, California.

Temecula Valley is a graben rift valley in western Riverside County, California, one of the valleys forming the Elsinore Trough along the Elsinore Fault Zone. It lies between the Wildomar Fault at the foot of the Temescal Mountains and the Willard Fault at the foot of the Santa Ana Mountains. Murrieta Creek and Temecula Creek drain it, and their confluence forms the Santa Margarita River. The original centers of Murrieta, Temecula and Wildomar stand within the valley.

The Pechanga Band of Luiseño Indians inhabited the valley long before European settlers arrived in the 1800s. This indigenous presence remains an important part of the region's heritage.

The name Temecula derives from the Luiseño village of Temecula, and the Spanish form Valle de Temecula is still used. The original town centers of Temecula, Murrieta and Wildomar lie within the valley, and the surrounding Temescal and Santa Ana mountains carry names from the same early Californian period.

Visiting by car is easiest since the valley lies between major cities and winery tours, along with outdoor activities, are accessible year-round. Plan for warm, dry summers and mild winters when organizing your trip.

The valley is a graben, a block of land dropped between two faults: the Wildomar Fault at the foot of the Temescal Mountains and the Willard Fault below the Santa Ana Mountains. Murrieta Creek and Temecula Creek meet inside it to form the Santa Margarita River, and the original town centers of Murrieta, Temecula and Wildomar all stand on this dropped block.