This mining town became the seat of justice of Mariposa County when on February 18,1850, the State Legislature divided the state into 27 counties. Mariposa County the comprised one-fifth of the entire state and included what are Mariposa, Tulare, Merced, Fresno, Kern, Madera, and portions of Los Angeles, San Bernardino, Inyo, Mono, and San Benito Counties. As a result of election on September 3, 1851, Mariposa became the seat of government on November 10, 1851.
Aqua Fria overlays the town's main street. On June 22, 1866, the entire town, about 75 buildings, was consumed by fire. The residents did not own the land, hence the town was never re-built.