{"nrhp_refnum":"73000421","name":"Plumas-Eureka Mill, Jamison Mines District","other_names":["Plumas-Eureka State Park District"],"category":"district","location":{"address":"W of Blairsden off Alt. U.S. 40 in Plumas-Eureka State Park","address_restricted":false,"city":"Blairsden","county":"Plumas County","state":"CA","lat":39.750653323500046,"lon":-120.71792581491096,"geom_source":"nps_gis"},"listed_date":"1973-07-16","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Industry"],"significance_levels":["state"],"summary":{"what_it_is":"A historic mining district within Plumas-Eureka State Park near Blairsden, Plumas County, California, covering about 594 acres. It includes the 1873 Plumas-Eureka Stamp Mill and a group of 1870s and 1890 mining-related buildings around the mill and the Jamison Mine.","why_significant":"The stamp mill is described as the largest and best preserved of its kind remaining in California. The surrounding boarding house, assay office, stable, tramway station and Jamison Mine buildings are valued as a complex that conveys the story of hard-rock gold mining in the state. The area was a highly productive mining operation from the 1870s through the 1880s.","narrative":"Within Plumas-Eureka State Park near Blairsden, California, a cluster of mining buildings preserves the story of hard-rock gold mining in the northern Sierra. The centerpiece is the 75-foot wooden stamp mill, built in 1873 and described as the largest and best preserved of its kind remaining in the state. Nearby stand a two-story boarding house, assay office, stable, tramway station and residence from the same period, along with a second group of 1890 structures at the Jamison Mine, including barracks, a blacksmith shop, a stone powder magazine, a barn, a warehouse and several miners' cabins. Most of these buildings are plain, but together they show how a large mining operation worked. The Sierra Buttes Mining Company consolidated local mines in 1872 and employed as many as 400 men during the 1870s and 1880s. Mining dwindled after 1890 and ended in 1943. The state acquired the first park lands in 1959, and the mill was partly restored in 1961.","period_of_significance":"19th Century","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Condition is marked deteriorated and altered. The stamp mill was partially restored in 1961, and most of the other buildings are sealed and used for storage or as workshops, with a few in fair or good structural condition.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:31.732291-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/73000421.pdf"},"photo":null,"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123860425","wikipedia":null,"wikidata":null},"indexable":true,"url":"https://nationalhistoricalregister.com/california/plumas-county/plumas-eureka-mill-jamison-mines-district-73000421/"}