{"nrhp_refnum":"00000397","name":"Allegheny River Lock and Dam No. 3","other_names":["New Lock No. 3"],"category":"structure","location":{"address":"Approx. 1 mi. N of Barrington","address_restricted":false,"city":"New Kensington","county":"Allegheny County","state":"PA","lat":40.53989131700004,"lon":-79.81117355595484,"geom_source":"nps_gis"},"listed_date":"2000-04-21","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Transportation","Maritime History","Architecture","Engineering"],"significance_levels":["state"],"summary":{"what_it_is":"A U.S. Army Corps of Engineers navigation facility on the Allegheny River, consisting of a lock, a fixed-crest dam, an esplanade, an operations building and a gauging station, located about 14.5 miles upstream from the river's mouth near New Kensington in Allegheny County, Pennsylvania. It was built in 1932-1934.","why_significant":"The nomination argues the lock and dam are significant for their role in the Allegheny River slackwater navigation system, which allowed barge and towboat access to industrial centers including New Kensington's aluminum plant. It also argues the 1932-1934 lock and dam is a representative example of its type and retains much of its original design and equipment.","narrative":"Located about 14.5 miles upstream from the mouth of the Allegheny River near New Kensington, Pennsylvania, this lock and dam was built by the U.S. Army Corps of Engineers in 1932-1934 to replace an older lock whose chamber, at 289 by 56 feet, had become too small for four-barge tows. The new lock chamber measures 56 by 360 feet and lifts boats 13.8 feet. The complex includes a reinforced concrete lock, a dam about 1,435 feet long, an esplanade, a two-story operations building with a flat rubber roof, and a gauging station. Vang Construction Company built the lock and operations building, and Seeds and Derham built the dam. The facility formed part of a slackwater system that gave commercial barges access to the river upstream and to the steel mills and aluminum plant in the New Kensington area. Its original design, layout and much of its machinery remain in place, which the nomination cites as the basis for its significance as a representative example of lock and dam construction from that period.","period_of_significance":"1903-1948","architect_builder":"Locks - Vang Construction Co.; Dam - Seeds & Derham","architectural_style":"Late Nineteenth and Early Twentieth Century Revival","criteria":["A","C"],"status_note":"Operating lock and dam; the old Lock 3 land wall remains and is used as a marina, and the locktenders' house is no longer owned by the Corps of Engineers.","vacant_flag":false,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:35.690063-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/00000397.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/00000397/7ad316bc5b-800.webp","url_1600":"https://nationalhistoricalregister.com/media/00000397/7ad316bc5b-1600.webp","licence":"Public domain","author":"U.S. Army Corps of Engineers","credit_html":"U.S. Army Corps of Engineers, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Allegheny_Islands_State_Park,_C.W._Bill_Young_Lock_and_Dam.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71992248","wikipedia":"https://en.wikipedia.org/wiki/Allegheny_River_Lock_and_Dam_No._3","wikidata":"https://www.wikidata.org/wiki/Q4731335"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/allegheny-county/allegheny-river-lock-and-dam-no-3-00000397/"}