Agua Fria, located one fourth mile north of Carson Creek, a tributary of Agua Fria, was the first county seat of Mariposa County in 1850-1851, one of California’s original 27 counties. Until 1852, while mining was the region’s main industry, Mariposa County comprised one sixth of the state and included all of what are now Merced, Madera, Fresno, Tulare, Kings, and Kern Counties. The town of Mariposa became the seat of government in 1852, and the courthouse was completed in 1854.