The Pomona Valley is located in the Greater Los Angeles Area between the San Gabriel Valley and San Bernardino Valley in Southern California. The valley is approximately 30 miles east of downtown Los Angeles which can often be seen from nearby foothills. It ranges from the city of San Dimas from the far west to Rancho Cucamonga to the Far East portion of the valley. The alluvial valley is formed by the Santa Ana River and its tributaries.