The river's source is in the San Bernardino Mountains, one of the Transverse Ranges, above Hesperia-San Bernardino. The West Fork of the Mojave flows into Silverwood Lake, formed by Cedar Springs Dam, which overflows in the Mojave River Forks Reserve area. On occasion, the lake releases water into the river. Downstream, Deep Creek meets the West Fork, forming the Mojave River immediately upstream of the Mojave Forks Dam, which provides flood control. Downstream of the dam, the Mojave River flows north and east, underground in most places, through Hesperia, Victorville, and Barstow.