The Parker Valley is located along the Lower Colorado River within the Lower Colorado River Valley region, in southwestern Arizona and southeastern California. Its natural habitats are within the Sonoran Desert (Arizona) and Colorado Desert (California) ecoregions. Riparian zone habitats on the river include Mesquite Bosques. The river has supported irrigated agricultural conversion of the valley's landscape. Geography Three major drainages of the Colorado River enter in the Parker Valley region. The Bill Williams River and Bouse Wash have confluences with the Colorado in the northern valley area, from watersheds on the east. Tyson Wash crosses the La Posa Plain and enters downstream, with its watershed east of the river in the Colorado River Indian Reservation. In California, the Vidal Valley and the Whipple Mountains border the Parker Valley on the northwest, and the Palo Verde Valley on the southwest. In Arizona the Buckskin Mountains border the valley on the north, the Cactus Plain and Dome Rock Mountains border it on the east. Populated places Settlements within Parker Valley include: Parker and Poston in Arizona; and Earp and Big River in California. It is at the northern area of the Colorado River Indian Reservation on the Colorado River, and is also at the northern perimeter of the La Posa Plain. See also References Arizona Atlas & Gazetteer, DeLorme, c. 2002, p. 70. Valleys of Arizona Valleys of California Valleys of the Lower Colorado River Valley Geography of the Colorado Desert Valleys of Riverside County, California Valleys of San Bernardino County, California Landforms of La Paz County, Arizona