{"nrhp_refnum":"66000788","name":"Tremont Street Subway","other_names":["Green Line"],"category":"structure","location":{"address":"Beneath Tremont, Boylston, and Washington Sts.","address_restricted":false,"city":"Boston","county":"Suffolk County","state":"MA","lat":42.35567396850004,"lon":-71.06306963724867,"geom_source":"nps_gis"},"listed_date":"1966-10-15","is_nhl":true,"nhl_designated_date":"1964-01-29","areas_of_significance":["Transportation"],"significance_levels":["national"],"summary":{"what_it_is":"A section of Boston's original subway tunnel and two station entrance kiosks beneath Tremont and Boylston Streets along Boston Common and the Public Garden, built 1895-1898 under Chief Engineer Howard A. Carsen and now part of the MBTA Green Line.","why_significant":"It was the first underground public transportation system in the United States and only the fifth in the world. Its success led quickly to a similar system in New York City. Boston also developed a hybrid steel-and-concrete tunnel method that became standard in American subway construction.","narrative":"Beneath Tremont and Boylston Streets, along Boston Common and the Public Garden, runs the first subway built in the United States. Ground was broken in 1895, and the first section opened on September 1, 1897, with the full system running by autumn 1898. It was built to relieve streetcar congestion on narrow downtown streets. Engineers combined features of London's deep tubes and Paris's shallow masonry arches to produce a steel and concrete tunnel built mainly in open excavation, a method soon standard across American subway construction. In its first full year the line carried about 50 million rides, and its success led quickly to a similar system in New York City. The section between Court Street and Charles Street remains much as built and still carries Green Line trains. Two original Classical Revival kiosks designed by Edward M. Wheelwright still stand along the Boston Common edge of Tremont Street above the Park Street and Boylston Street stations.","period_of_significance":"1897-98","architect_builder":"Chief Engineer: Howard A. Carsen","architectural_style":"Classical Revival (entrance and exit kiosks, designed by Edward M. Wheelwright)","criteria":[],"status_note":"Still in regular operation as part of the MBTA Green Line; the Boylston Street Station and the Park and Boylston kiosks are described as essentially unaltered, and Park Street Station has been enlarged on the northbound side.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 01:59:36.584911-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/5/7939/63793905/content/electronic-records/rg-079/NPS_MA/66000788_NHL.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/66000788/0414f39f8d-800.webp","url_1600":"https://nationalhistoricalregister.com/media/66000788/0414f39f8d-1600.webp","licence":"Public domain","author":"Boston Transit Commission","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Pleasant_Street_Incline_junction.jpg\" rel=\"noopener\">Boston Transit Commission</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Pleasant_Street_Incline_junction.jpg"},"district":{"nrhp_refnum":"72000144","name":"Boston Common and Public Garden","url":"https://nationalhistoricalregister.com/districts/massachusetts/boston-common-and-public-garden-72000144/"},"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/63793905","wikipedia":"https://en.wikipedia.org/wiki/Tremont_Street_subway","wikidata":"https://www.wikidata.org/wiki/Q2451368"},"indexable":true,"url":"https://nationalhistoricalregister.com/massachusetts/suffolk-county/tremont-street-subway-66000788/"}