{"nrhp_refnum":"13000140","name":"Empire Mine Historic District (Boundary Increase)","other_names":["Empire Mine State Historic Park","Calif. Hist. Landmark No.298, P-29-003144, ASC-21-08-2246"],"category":"district","location":{"address":null,"address_restricted":true,"city":"Grass Valley","county":"Nevada County","state":"CA","lat":39.2036,"lon":-121.043,"geom_source":"wikidata"},"listed_date":"2013-04-10","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Industry","Architecture","Landscape Architecture","Historic - Non-Aboriginal"],"significance_levels":["local"],"summary":null,"photo":{"url_800":"https://nationalhistoricalregister.com/media/13000140/cfe5faf1f2-800.webp","url_1600":"https://nationalhistoricalregister.com/media/13000140/cfe5faf1f2-1600.webp","licence":"CC BY 2.5","author":"Beej71","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Empire_mine_shaft.jpg\" rel=\"noopener\">Beej71</a>, <a href=\"https://creativecommons.org/licenses/by/2.5\" rel=\"license noopener\">CC BY 2.5</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Empire_mine_shaft.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":null,"wikipedia":"https://en.wikipedia.org/wiki/Empire_Mine_State_Historic_Park","wikidata":"https://www.wikidata.org/wiki/Q5374101"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/nevada-county/empire-mine-historic-district-boundary-increase-13000140/"}