{"nrhp_refnum":"04000170","name":"La Grange Lock and Dam Historic District","other_names":["Lock and Dam 8"],"category":"district","location":{"address":"0.75 mi. S of Cty Rte 795N at Illinois River","address_restricted":false,"city":"Versailles","county":"Brown County","state":"IL","lat":39.94268291800006,"lon":-90.5338881945451,"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 federal lock and dam complex on the Illinois River about 80 miles north of Grafton, near Versailles in Brown County, Illinois. It was placed in operation in 1939 and includes a lock, a dam and a control station.","why_significant":"It is significant under Criterion A for its role in the maritime and transportation history of the Illinois Waterway, a slackwater system giving commercial barges access between Chicago and the Mississippi River. It is significant under Criterion C as a good representative example of Army Corps of Engineers lock and dam construction of the period. It retains a high degree of integrity despite some replaced equipment and surfaces.","narrative":"La Grange Lock and Dam is a navigation facility on the Illinois River in Brown County, Illinois, placed in operation in 1939. It is the southernmost lock and dam of the Illinois Waterway. The district has a lock with an 11-foot lift and a 110 by 600 foot chamber, a 1,066-foot concrete and earthen dam with wicket gates and a Tainter gate, and a two-story brick control station designed by Army Corps engineer Paul LeGromwell. The control station was built with key operations on the upper floor so the lower story could be cleared of flood mud and debris. It was the last of the 1930s lock and dams on the waterway. It was listed for its part in the system that lets barges and towboats travel between Chicago and the Mississippi, and as a representative example of Army Corps of Engineers design of its period. Two later boats, a maneuver boat and a push boat, are not counted as historic. The facility keeps a high degree of integrity.","period_of_significance":"1939-1951","architect_builder":"LeGromwell, Paul","architectural_style":"No Style: control station; Other: lock and dam","criteria":["A","C"],"status_note":"Still operating; the lock and dam retain their original appearance and function, with some equipment and surfaces replaced. The maneuver boat is still used to raise and lower the dam wickets.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.48885-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/25/8907/28890725/content/electronic-records/rg-079/NPS_IL/04000170.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/04000170/2d551d09b9-800.webp","url_1600":"https://nationalhistoricalregister.com/media/04000170/2d551d09b9-1600.webp","licence":"Public domain","author":"Brian Grogan","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:La_Grange_Lock_and_Dam_Aerial_View.jpg\" rel=\"noopener\">Brian Grogan</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:La_Grange_Lock_and_Dam_Aerial_View.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28890725","wikipedia":"https://en.wikipedia.org/wiki/La_Grange_Lock_and_Dam","wikidata":"https://www.wikidata.org/wiki/Q16893851"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/brown-county/la-grange-lock-and-dam-historic-district-04000170/"}