{"nrhp_refnum":"04000167","name":"Lockport Lock, Dam and Power House Historic District","other_names":["Lock 2 and Controlling Works"],"category":"district","location":{"address":"2502 Channel Dr.","address_restricted":false,"city":"Lockport","county":"Will County","state":"IL","lat":41.57115328000006,"lon":-88.07780200149953,"geom_source":"nps_gis"},"listed_date":"2004-03-10","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Transportation","Maritime History","Engineering"],"significance_levels":["national"],"summary":{"what_it_is":"A historic district of locks, a dam, a powerhouse and a control station on the Des Plaines/Illinois River just south of Lockport, Will County, Illinois, built in stages between 1905 and 1933 by the Chicago Sanitary District and the State of Illinois, with federal completion.","why_significant":"The district is significant under Criteria A and C as an example of the lock, dam, control station and powerhouse property types of the Illinois Waterway Navigation System. It was a crucial part of the slackwater system that gave commercial barges access between Chicago and the Mississippi River. It also shows early hydroelectric development and rare lock gate engineering.","narrative":"Lockport Lock, Dam and Power House is a cluster of waterway structures on the Des Plaines River just south of Lockport, Illinois. It includes an old Chicago Sanitary District lock (1905-10), a concrete dam, an Italian Renaissance powerhouse designed by Frederick L. Barrett and placed in operation in 1908, a brick control station, and a large new lock opened in 1933. The new lock has a 40-foot lift, the largest on the Illinois Waterway, and its upstream single-leaf, submergible vertical-lift gates are described as rare. The district was listed because it shows how the Chicago Sanitary and Ship Canal, hydroelectric generation and the Great-Lakes-to-the-Gulf waterway came together. Built in stages by the Sanitary District, the State of Illinois and the federal government, the complex helped open 336 miles of waterway to commercial barge traffic between Chicago and the Mississippi River. The lock and dam still operate, and the powerhouse is being renovated.","period_of_significance":"1905-1952","architect_builder":"Barrett, Frederick L.; Smith, Walter Mickle","architectural_style":"Late 19th and 20th Century Revivals: Italian Renaissance","criteria":["A","C"],"status_note":"The 1933 lock and dam are still operating, the powerhouse is remotely operated and being renovated for continued and increased use, and the old Chicago Sanitary District lock has been unused since 1933.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.783517-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/88/8914/28891488/content/electronic-records/rg-079/NPS_IL/04000167.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/04000167/d5f78d989a-800.webp","url_1600":"https://nationalhistoricalregister.com/media/04000167/d5f78d989a-1600.webp","licence":"CC BY-SA 3.0","author":"Dan Brownlee","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Lock_Number_1_Lockport_IL.jpg\" rel=\"noopener\">Dan Brownlee</a>, <a href=\"https://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_Number_1_Lockport_IL.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28891488","wikipedia":"https://en.wikipedia.org/wiki/Lockport_Powerhouse","wikidata":"https://www.wikidata.org/wiki/Q6665748"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/will-county/lockport-lock-dam-and-power-house-historic-district-04000167/"}