This geologic database is a digitized version of the original 1:24,000-scale analog geologic map titled "Geologic map of the Parker NW, Parker, and parts of the Whipple Mountains SW and Whipple Wash quadrangles, California and Arizona", published by the U.S. Geological Survey (USGS) in 1980. The map area straddles the Arizona-California border and includes the community of Parker, AZ, and the southeastern part of the Whipple Mountains, where the prominent Whipple Mountains Detachment Fault separates lower plate Cretaceous and older gneisses from upper plate crystalline, volcanic, and sedimentary rocks. The Whipple Mountains are surrounded by numerous Neogene sedimentary units that record the arrival and subsequent fluctuations of the Colorado River in the region from the Pliocene through the Holocene, as well as Quaternary alluvial fan processes on the southern flank of the Whipple Mountains and in lower Vidal Valley.