{"nrhp_refnum":"66000236","name":"New Almaden","other_names":["New Almaden Historic District"],"category":"district","location":{"address":"14 mi. S of San Jose on CR G8","address_restricted":false,"city":"San Jose","county":"Santa Clara County","state":"CA","lat":37.17842154700003,"lon":-121.81951209599998,"geom_source":"nps_gis"},"listed_date":"1966-10-15","is_nhl":true,"nhl_designated_date":"1961-07-04","areas_of_significance":["Industry"],"significance_levels":["national"],"summary":{"what_it_is":"Former mercury (quicksilver) mining town and mine district at New Almaden, near San Jose in Santa Clara County, California, with mining operations beginning in the 1840s and buildings from the 1850s onward.","why_significant":"The New Almaden Mine was the first quicksilver deposit discovered in North America and one of the world's four major sources of quicksilver. Its mercury enabled the rapid growth of gold and silver quartz mining in California and the Comstock Lode in Nevada. It is California's oldest mine and its most valuable single mine, producing over $70,000,000 in quicksilver.","narrative":"New Almaden is a former mercury mining town south of San Jose, California, now a quiet residential village along a wooded creek canyon. The settlement grew around the first quicksilver deposit discovered in North America, which was claimed in 1845 by Andreas Castillero. Under Henry W. Halleck, large-scale production began in 1850, and output reached about a million pounds a year by 1854. Because quicksilver was used to recover gold and silver from ore, the mine supplied the California gold fields and the Comstock Lode, and by 1865 it provided 60 percent of mercury consumed in California and Nevada. Surviving features include Casa Grande, the 1850s superintendent's residence of adobe and brick, early adobes, board-and-batten miners' cottages, a toll house and St. Anthony's Church of 1900. On Mine Hill, a school, store walls, brick chimneys, flumes and shafts remain. The area was recognized as a historic district for its central role in the mining frontier.","period_of_significance":"1845 to present","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Town is now a largely residential village; Casa Grande operates as a club, a museum occupies an adobe, and Mine Hill is closed to visitors because of old shafts. The mine was worked sporadically, and Mine Hill School has been vacant since 1940.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:31.327883-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/66000236_NHL.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/66000236/a9a31fecbc-800.webp","url_1600":"https://nationalhistoricalregister.com/media/66000236/a9a31fecbc-1600.webp","licence":"Public domain","author":"Carleton Watkins","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:New_Alm_smelter.jpg\" rel=\"noopener\">Carleton Watkins</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:New_Alm_smelter.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123857895","wikipedia":"https://en.wikipedia.org/wiki/New_Almaden","wikidata":"https://www.wikidata.org/wiki/Q7005296"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/santa-clara-county/new-almaden-66000236/"}