{"nrhp_refnum":"04000177","name":"Lock and Dam No. 17 Historic District","other_names":[],"category":"district","location":{"address":"173 Lock and Dam Rd.","address_restricted":false,"city":"New Boston","county":"Mercer County","state":"IL","lat":41.19169586050006,"lon":-91.06258466271836,"geom_source":"nps_gis"},"listed_date":"2004-03-10","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Transportation","Maritime History","Commerce","Social History","Conservation","Economics","Politics/Government","Military"],"significance_levels":["national"],"summary":{"what_it_is":"An 86.93-acre federal navigation complex on the Upper Mississippi River near New Boston, Mercer County, Illinois, made up of a lift lock, an incomplete auxiliary lock, a non-navigable dam and associated buildings, structures and objects. Most of it was built between 1935 and 1938 and put in operation on May 14, 1939.","why_significant":"The district is significant for its role in the Upper Mississippi River 9-Foot Navigation Project, in transportation, maritime history, commerce, conservation, military, economics, politics/government and social history. It was the 20th complex of the 1931-1940 project and one of the last funded with emergency relief money. Its construction shows the residential work-camp life of relief workers at a remote site.","narrative":"Lock and Dam No. 17 crosses the Upper Mississippi River near New Boston, Illinois, in a rural setting of marshes, sloughs and islands. The 86.93-acre complex includes a main lock with an 8-foot lift, an incomplete auxiliary lock, a dam with eight Tainter gates and three roller gates, earthen dikes, a Moderne-style central control station and a lawn esplanade. Contractors built most of it between 1935 and 1938, and it opened to navigation on May 14, 1939. It was among the last locks in the 9-foot channel project paid for with emergency relief funds. The site was so remote that a 3.7-mile access road and a worker camp with eleven bunk houses and a mess hall were built first; 626 men worked there at the 1936 peak. Later additions include 1951 guide wall extensions to correct outdraft problems and a 1991 rehabilitation. The lock, auxiliary lock, dam, control station and two stage recorders contribute to the district's historic character.","period_of_significance":"1935-1948","architect_builder":"U.S. Army Corps of Engineers, Rock Island District; Edwin E. Abbott","architectural_style":"Lock and dam; Moderne (central control station); machinery","criteria":["A"],"status_note":"In continuous use as part of the navigation system since May 14, 1939; the lock and dam had a 50-year major rehabilitation in 1991 and are described as being in excellent condition.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:37.508117-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/71/8913/28891371/content/electronic-records/rg-079/NPS_IL/04000177.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/04000177/50c74adbd8-800.webp","url_1600":"https://nationalhistoricalregister.com/media/04000177/50c74adbd8-1600.webp","licence":"Public domain","author":"USGS","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Mississippi_River_Lock_and_Dam_number_17.jpg\" rel=\"noopener\">USGS</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Mississippi_River_Lock_and_Dam_number_17.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/28891371","wikipedia":"https://en.wikipedia.org/wiki/Lock_and_Dam_No._17","wikidata":"https://www.wikidata.org/wiki/Q6665266"},"indexable":true,"url":"https://nationalhistoricalregister.com/illinois/mercer-county/lock-and-dam-no-17-historic-district-04000177/"}