History of the Almaden Quicksilver Mines

The Almaden Quicksilver mines give Almaden Valley its name and its most distinctive historical identity. These mercury mines operated from 1845 through the 1970s and were among the most productive in North America.

Origins

The mines were named after the famous Almaden mercury mines in Spain. Mexican settlers discovered cinnabar deposits in the hills south of San Jose in the 1840s. The timing was fortuitous — mercury was essential for processing gold and silver ore, and the California Gold Rush of 1848 created enormous demand.

Peak Production

During the Civil War era and beyond, the New Almaden mines produced millions of flasks of mercury. The mining operation supported a community of several hundred workers and their families in the town of New Almaden, which included company housing, a general store, a school, and a church.

The Mining Town of New Almaden

New Almaden at the southern end of Almaden Road preserves the architectural character of the mining era. The Casa Grande, a twenty-seven room mansion built for the mine manager, still stands and now operates as part of the New Almaden Quicksilver Mining Museum. The surrounding town features Victorian-era cottages and the Hacienda Cemetery.

Environmental Legacy

Mercury contamination from the mining operations left a lasting environmental footprint. Cleanup efforts have addressed the most contaminated areas, but some restrictions remain on land use within the former mining zone. The county park that now occupies the mine site includes interpretive signage explaining the environmental remediation.

Visiting Today

Almaden Quicksilver County Park encompasses the former mine property. Visitors can hike to mine ruins, the Hacienda furnace site, and the Almaden mining museum. The English Camp, Senator Mine, and Randol Trail provide access to historical mining features.

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