{"nrhp_refnum":"04000166","name":"Starved Rock Lock and Dam Historic District","other_names":["Lock and Dam 6"],"category":"district","location":{"address":"950 N 27th Rd.","address_restricted":false,"city":"Ottawa","county":"LaSalle County","state":"IL","lat":41.32310448100006,"lon":-88.9868955550848,"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 federally owned lock and dam complex on the Illinois River near Ottawa and Utica, La Salle County, Illinois, built from 1926 to 1933. It includes a lock, a concrete dam and a brick control station.","why_significant":"The district is significant under Criterion A for its role in the maritime, transportation and industrial history of the Illinois Waterway, a slackwater system that let commercial barges travel between Chicago and the Mississippi River. It is significant under Criterion C as a good example of Army Corps of Engineers-approved lock and dam construction of its period. The lock and dam retain original appearance and function and a high degree of integrity.","narrative":"Starved Rock Lock and Dam sits on the Illinois River in La Salle County, beneath limestone bluffs of Starved Rock State Park. Built between 1926 and 1933, it includes a lock with a 25-foot lift and a 110 by 600 foot chamber, a 1,280-foot concrete dam, and a red brick control station with gabled bays that recall the Jacobethan style. State of Illinois engineers led by Walter Mickle Smith designed the lock, and the US Army Corps of Engineers completed it. When built in 1929, its Tainter gates reportedly ranked among the largest in the country. The complex was part of a slackwater system that gave commercial barges and towboats access to the 336-mile waterway between Chicago and the Mississippi River. It was recognized for its contribution to regional transportation and industrial history and as a representative example of Corps lock and dam design. It still operates, with replaced machinery, a later power house, and a visitor center added in 1978.","period_of_significance":"1926-33","architect_builder":"Smith, Walter Mickle","architectural_style":"Other: lock and dam; No style: control station","criteria":["A","C"],"status_note":"Still an operating lock and dam facility; some equipment and surfaces have been replaced, and a power house was added to the dam in 1993-95.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.365394-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/9/8913/28891309/content/electronic-records/rg-079/NPS_IL/04000166.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/04000166/9063da76fc-800.webp","url_1600":"https://nationalhistoricalregister.com/media/04000166/9063da76fc-1600.webp","licence":"Public domain","author":"U.S. Army Corps of Engineers, photographer not specified or unknown","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:USACE_Starved_Rock_Lock_and_Dam.jpg\" rel=\"noopener\">U.S. Army Corps of Engineers, photographer not specified or unknown</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:USACE_Starved_Rock_Lock_and_Dam.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28891309","wikipedia":"https://en.wikipedia.org/wiki/Starved_Rock_Lock_and_Dam","wikidata":"https://www.wikidata.org/wiki/Q7602645"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/lasalle-county/starved-rock-lock-and-dam-historic-district-04000166/"}