{"nrhp_refnum":"73000426","name":"Folsom Powerhouse","other_names":[],"category":"building","location":{"address":"Off Folsom Blvd. in Folsom Lake State Recreation Area","address_restricted":false,"city":"Folsom","county":"Sacramento County","state":"CA","lat":38.680180534000044,"lon":-121.17692725786407,"geom_source":"nps_gis"},"listed_date":"1973-10-02","is_nhl":true,"nhl_designated_date":"1981-05-29","areas_of_significance":["Industry","Engineering"],"significance_levels":["national"],"summary":{"what_it_is":"A hydroelectric generating plant at Folsom, Sacramento County, California, built in 1895 beside the American River within Folsom Lake State Recreation Area, with a smaller frame lower powerhouse added in 1897.","why_significant":"The plant marked one of the first successful uses of hydroelectric power in the world and showed that electricity could be transmitted over long distances. Its power travelled 22 miles to Sacramento, where it ran street railways and lighting. It is also California Historical Landmark No. 633.","narrative":"Built in 1895 on the American River at Folsom, this hydroelectric plant sent power 22 miles to Sacramento. The main building has two stories, with a granite lower level, thick walls and a corrugated iron roof. Eight-foot inlet pipes fed four pairs of turbines connected to generators that were the largest three-phase dynamos built up to that time. A smaller frame powerhouse from 1897 holds a fifth generator driven by rope and pulley, and now serves as a museum. The Folsom Water Power Company, led by Horatio P. Livermore, built the plant with General Electric equipment when many doubted that current could travel far. On July 13, 1895, the switch was thrown and lights came on in Sacramento, which later held an electric carnival. Pacific Gas and Electric acquired the plant in 1905 and donated it to the state in 1952. It is California Historical Landmark No. 633.","period_of_significance":"19th Century (specific date 1895)","architect_builder":"Folsom Water Power Company (Horatio P. Livermore, Charles E. Livermore, Albert Gallatin); equipment supplied by General Electric Company","architectural_style":null,"criteria":[],"status_note":"Canal is dry and the building no longer generates power; structures are described as mostly in good condition, with the lower powerhouse maintained and used as a museum. Owned by the California Department of Parks and Recreation.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:32.060026-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/73000426.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/73000426/3070ed8caa-800.webp","url_1600":"https://nationalhistoricalregister.com/media/73000426/3070ed8caa-1600.webp","licence":"CC BY-SA 4.0","author":"The Oaked Ridge","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Folsom_Powerhouse_Close.JPG\" rel=\"noopener\">The Oaked Ridge</a>, <a href=\"https://creativecommons.org/licenses/by-sa/4.0\" rel=\"license noopener\">CC BY-SA 4.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Folsom_Powerhouse_Close.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123860590","wikipedia":"https://en.wikipedia.org/wiki/Folsom_Powerhouse_State_Historic_Park","wikidata":"https://www.wikidata.org/wiki/Q5464868"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/sacramento-county/folsom-powerhouse-73000426/"}