{"nrhp_refnum":"73000294","name":"Hoosac Tunnel","other_names":[],"category":"structure","location":{"address":"From North Adams on the W to the Deerfield River on the E","address_restricted":false,"city":"North Adams","county":"Berkshire County","state":"MA","lat":42.675078074000055,"lon":-73.04482881344998,"geom_source":"nps_gis"},"listed_date":"1973-11-02","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Commerce","Engineering","Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"A railroad tunnel, 25,081 feet long, bored through Hoosac Mountain between Florida and North Adams in Berkshire County, Massachusetts. It was completed in 1875 and is still in railroad use.","why_significant":"The nomination presents the tunnel as an extraordinary engineering accomplishment that symbolizes industrialization and commercial growth in nineteenth-century Massachusetts. It was built to give the state a northerly rail route to the west after the Erie Canal diverted commerce. Construction relied on power drills, nitro-glycerin and electric igniting devices, and the tunnel remained a vital link for freight into the twentieth century.","narrative":"Hoosac Tunnel carries a railroad line 25,081 feet through Hoosac Mountain, linking North Adams and Florida in western Massachusetts. Cut mostly through mica slate, it averages 24 feet wide and 20 feet high. Crews worked from both portals and from a 1,028-foot central shaft, which later served for ventilation. Conceived for the Troy and Greenfield Railroad, the project was backed by state loans and eventually taken over by the Commonwealth in 1862. Power drills, nitro-glycerin and electric igniting devices sped the work, and the first commercial passenger train ran through on October 13, 1875. The cost included over one hundred lives and more than twenty-eight million dollars. The state sold the tunnel to the Fitchburg Railroad in 1885, and the Boston and Maine acquired it in 1919. It was enlarged in 1925 and repaired after a 1972 roof collapse. Listing recognizes its engineering and its role in transportation and commerce.","period_of_significance":"19th Century (specific date 1875)","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Still in use as a railroad tunnel; the form rates its condition as good and altered, noting a 1972 roof collapse that was reinforced with steel plates.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:11:53.881485-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/52/7943/63794352/content/electronic-records/rg-079/NPS_MA/73000294.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/73000294/24ad20b284-800.webp","url_1600":"https://nationalhistoricalregister.com/media/73000294/24ad20b284-1600.webp","licence":"CC BY-SA 2.0","author":"Doug Kerr from Albany, NY, United States","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Hoosac_Tunnel_east_portal,_April_2013.jpg\" rel=\"noopener\">Doug Kerr from Albany, NY, United States</a>, <a href=\"https://creativecommons.org/licenses/by-sa/2.0\" rel=\"license noopener\">CC BY-SA 2.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Hoosac_Tunnel_east_portal,_April_2013.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/63794352","wikipedia":"https://en.wikipedia.org/wiki/Hoosac_Tunnel","wikidata":"https://www.wikidata.org/wiki/Q1466913"},"indexable":true,"url":"https://nationalhistoricalregister.com/massachusetts/berkshire-county/hoosac-tunnel-73000294/"}