{"nrhp_refnum":"71000526","name":"Lock 18 of Enlarged Erie Canal","other_names":["Double Lock"],"category":"structure","location":{"address":"W of 252 N. Mohawk St., E of Reservoir St. near Manor Ave.","address_restricted":false,"city":"Cohoes","county":"Albany County","state":"NY","lat":42.78553342300006,"lon":-73.71169702099996,"geom_source":"nps_gis"},"listed_date":"1971-02-18","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["national"],"summary":{"what_it_is":"Lock 18 of the Enlarged Erie Canal, also called the \"Double Lock,\" is a cut-stone canal lock structure in Cohoes, Albany County, New York, built between 1837 and 1842. Only the masonry remains today.","why_significant":"The lock was part of a scheme to reduce the number of locks between Albany and Schenectady, easing travel on one of the canal's most difficult stretches. Promoters of the Enlarged Canal believed larger, doubled locks would strengthen New York's economy and blunt competition from railways. It is described as a fine specimen of canal-era masonry work.","narrative":"Lock 18 of the Enlarged Erie Canal, known as the \"Double Lock,\" sits in Cohoes, Albany County, west of North Mohawk Street and near Reservoir Street. Built between 1837 and 1842, it is made of cut stone laid in a random ashlar pattern, with blocks averaging about three feet long, two feet high and one and one-half feet wide. The wooden gates have disappeared and the lock now holds no water, leaving only the masonry. It was part of an effort to cut the number of locks between Albany and Schenectady, which made travel faster and easier on one of the canal's hardest sections. Backers of the Enlarged Canal expected that doubling the locks and enlarging both locks and channel would strengthen the state's economy and reduce the threat from railways. The stone was generally Amsterdam stone. Engineer I Holmes Hutchinson prepared the lock plans used in construction. The lock is valued as a fine example of canal-era masonry.","period_of_significance":"1837 - 1842","architect_builder":"Plans for the locks by John B. Jervis is not stated; the form names I Holmes Hutchinson (1794-1865), civil engineer, whose plans for the Enlarged Canal locks were used for construction","architectural_style":null,"criteria":[],"status_note":"Condition listed as deteriorated and altered; only the masonry construction remains, the wooden gates are gone, and the lock contains no water. Present use is given as ruins.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:50:39.128707-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_NY/71000526.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/71000526/8a643cfd24-800.webp","url_1600":"https://nationalhistoricalregister.com/media/71000526/8a643cfd24-1600.webp","licence":"CC BY-SA 3.0","author":"Daniel Case","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Lock_18,_Enlarged_Erie_Canal.jpg\" rel=\"noopener\">Daniel Case</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:Lock_18,_Enlarged_Erie_Canal.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/75316267","wikipedia":"https://en.wikipedia.org/wiki/Lock_18_of_Enlarged_Erie_Canal","wikidata":"https://www.wikidata.org/wiki/Q6665209"},"indexable":true,"url":"https://nationalhistoricalregister.com/new-york/albany-county/lock-18-of-enlarged-erie-canal-71000526/"}