Francis Marion Smith (February 2, 1846 – August 27, 1931) (once known nationally and internationally as "Borax Smith" and "The Borax King" ) was an American miner, business magnate and civic builder in the Mojave Desert, the San Francisco Bay Area, and Oakland, California. Frank Smith created the extensive interurban public transit Key System, which operated in Oakland, the East Bay, and San Francisco.