Vidal Valley is a 20-mile (32 km) long valley in the far eastern Colorado Desert bordering the Colorado River. Most of the valley is in eastern San Bernardino County, California, but the outfall on the Colorado River is in northeast Riverside County. Vidal Valley forms the large border of the south side of the east-west block of the Whipple Mountains massif, the landform that forces the Colorado to flow southeast, then back southwest. The southeast exit of the valley into Parker Valley on the Colorado River skirts the north end of the Riverside Mountains (see photo). The Colorado River Aqueduct crosses the midpoint of the valley at Vidal Junction, California. The Vidal Valley also lies due east of the Danby Dry Lake landform.