{"nrhp_refnum":"72000117","name":"Middlesex Canal","other_names":[],"category":"district","location":{"address":"Running SE between towns of Lowell and Woburn","address_restricted":false,"city":"Woburn","county":"Middlesex County","state":"MA","lat":42.579919500000045,"lon":-71.24298633943417,"geom_source":"nps_gis"},"listed_date":"1972-08-21","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Commerce","Engineering","Transportation"],"significance_levels":["national"],"summary":{"what_it_is":"The Middlesex Canal is a 27.25-mile canal district running southeasterly through Lowell, Chelmsford, Billerica, Wilmington and Woburn, Massachusetts, from the Merrimack River to the Charles River in Boston. It was completed in 1803 under James Sullivan and engineer Loammi Baldwin.","why_significant":"The nomination calls it the oldest canal of its size built in the United States and a model for later projects such as the Erie Canal. Its construction brought several engineering firsts to the country, including hydraulic cement and the wye level. It opened inland markets and raw materials to Boston.","narrative":"Running 27.25 miles from the Merrimack River at Lowell to the Charles River in Boston, the Middlesex Canal was completed in 1803, ten years after its incorporation. Planned under James Sullivan and engineered by Loammi Baldwin, it originally had twenty locks, eight aqueducts and forty-eight bridges, with the Concord River at North Billerica as its main water supply. The nomination describes it as the oldest canal of its size in the United States and a model for the Erie Canal, which New York officials came to study in 1817. Baldwin introduced hydraulic cement and the wye level to American work, and a steam tug was tried on the canal in 1812. Traffic peaked in the 1820s and 1830s, then declined after the Boston and Lowell Railroad opened in 1835. Operations ceased by 1853. Today the Shawsheen Aqueduct piers and stretches of trough and towpath survive, while much of the eastern route has been lost to development.","period_of_significance":"19th Century (specific date 1803)","architect_builder":"Loammi Baldwin, engineer and builder; James Sullivan, organizational leader","architectural_style":null,"criteria":[],"status_note":"Condition marked deteriorated and altered. Most locks, bridges and aqueducts have disappeared, though sections of the trough and towpath remain visible in Lowell, Chelmsford, Billerica, Wilmington and north Woburn. Suburban growth threatens the remaining sections.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:11:54.599924-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/18/7961/63796118/content/electronic-records/rg-079/NPS_MA/72000117.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/72000117/b48d3d454f-800.webp","url_1600":"https://nationalhistoricalregister.com/media/72000117/b48d3d454f-1600.webp","licence":"CC BY-SA 3.0","author":"Daderot at English Wikipedia","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Middlesex_Canal,_Wilmington,_Massachusetts.JPG\" rel=\"noopener\">Daderot at English Wikipedia</a>, <a href=\"http://creativecommons.org/licenses/by-sa/3.0/\" rel=\"license noopener\">CC BY-SA 3.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Middlesex_Canal,_Wilmington,_Massachusetts.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/63796118","wikipedia":"https://en.wikipedia.org/wiki/Middlesex_Canal","wikidata":"https://www.wikidata.org/wiki/Q1931907"},"indexable":true,"url":"https://nationalhistoricalregister.com/massachusetts/middlesex-county/middlesex-canal-72000117/"}