According to the U.S. Census Bureau, the county has a total area of , of which is land and (1.3%) is water. It is the fourth-largest county in California by area. At roughly wide in the east-west dimension, the area of the county is massive. Riverside County, California is roughly the size of the State of New Jersey in total area. County government documents frequently cite the Colorado River town of Blythe as being a three-hour drive from the county seat, Riverside. Some view the areas west of San Gorgonio Pass as the Inland Empire portion of the county and the eastern part as either the Mojave Desert or Colorado Desert portion. There are probably at least three geomorphic provinces: the Inland Empire western portion, the Santa Rosa Mountains communities such as Reinhardt Canyon, and the desert region. Other possible subdivisions include tribal lands, the Colorado River communities, and the Salton Sea.