Mount Ophir, California

Mount Ophir is a ghost town in Mariposa County, California, United States. Founded in 1850 during the California Gold Rush, it was the site of the Mount Ophir Mint, an assay and stamping operation that produced octagonal $50 gold slugs under the authority of Augustus Humbert, the first U.S. Assayer of Gold in California.

The settlement grew along a main road in the southern Sierra Nevada foothills and supported stores, a hotel, and mining operations during the early 1850s. The area's mining claims later became the subject of Merced Mining Co. v. Frémont (1859), a case decided by the Supreme Court of the United States (58 U.S. 542). A post office operated under the name "Ophir" from 1852, changed to "Mount Ophir" in 1856 to avoid confusion with Ophir in Placer County.

Mount Ophir declined after the mint closed in 1853 and miners moved to more productive sites. The town was largely abandoned by the late 1850s. Ruins of the stamping mill and stone trading post foundations remain at the site.