{"nrhp_refnum":"00000396","name":"Allegheny River Lock and Dam No. 2","other_names":["New Lock No. 2"],"category":"structure","location":{"address":"7451 Lockway W","address_restricted":false,"city":"Pittsburgh","county":"Allegheny County","state":"PA","lat":40.49107747800005,"lon":-79.91358480122649,"geom_source":"nps_gis"},"listed_date":"2000-04-21","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Transportation","Maritime History","Engineering"],"significance_levels":["state"],"summary":{"what_it_is":"A U.S. Army Corps of Engineers navigation lock and dam on the Allegheny River within the City of Pittsburgh, Allegheny County, Pennsylvania, built 1932-1934 at the foot of the Highland Park cliffs. It includes a lock, fixed-crest dam, esplanade, operations building (powerhouse), and City of Pittsburgh sewer outlets.","why_significant":"The nomination argues the lock and dam are significant for their role in the Allegheny River slackwater navigation system, which allowed commercial barge and towboat traffic to reach industrial centers upriver. It also argues the facility is a representative example of lock and dam construction of 1932-1934 that retains its original appearance, function and much of its equipment.","narrative":"Lock and Dam No. 2 is a reinforced concrete navigation complex on the Allegheny River in Pittsburgh, built by the U.S. Army Corps of Engineers between 1932 and 1934 at the foot of the Highland Park cliffs. The lock measures 56 by 360 feet with an eleven-foot lift, and its steel miter gates and valves are operated by hydraulic pistons. A 1,393-foot fixed-crest dam, roughly 40 feet high, spans the river with no spillway. Vang Construction Company built the lock, dam and operations building. The two-story powerhouse, with its hydraulic pumps and water turbines, supplied the lock's hydraulic system. The facility replaced old Lock 2, whose chamber had become too small for standard barges and towboats by the 1920s. Its larger chamber allowed a four-barge tow to pass without breaking up. The complex is regarded as a representative example of 1930s lock construction that retains its original design and much of its equipment.","period_of_significance":"1903-1948","architect_builder":"Vang Construction Company (builder)","architectural_style":"Late Nineteenth and Early Twentieth Century Revival","criteria":["A","C"],"status_note":"Lock remains in operation; the operations building was pargeted circa 1988 and some original windows have been replaced.","vacant_flag":false,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:36.823253-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/00000396.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/00000396/c3ed4821b8-800.webp","url_1600":"https://nationalhistoricalregister.com/media/00000396/c3ed4821b8-1600.webp","licence":"Public domain","author":"Margaret Luzier, U.S. Army Corps of Engineers","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:USACE_Lock_and_Dam_2_Allegheny.jpg\" rel=\"noopener\">Margaret Luzier, U.S. Army Corps of Engineers</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:USACE_Lock_and_Dam_2_Allegheny.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71992256","wikipedia":"https://en.wikipedia.org/wiki/Allegheny_River_Lock_and_Dam_No._2","wikidata":"https://www.wikidata.org/wiki/Q4731334"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/allegheny-county/allegheny-river-lock-and-dam-no-2-00000396/"}