{"nrhp_refnum":"88000841","name":"Marion Bridge","other_names":[],"category":"structure","location":{"address":"LR 451 over Mon River","address_restricted":false,"city":"Point Marion","county":"Fayette County","state":"PA","lat":39.739413425000066,"lon":-79.90509269899997,"geom_source":"nps_gis"},"listed_date":"1988-06-22","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["state"],"summary":{"what_it_is":"A multiple span steel cantilever through truss bridge carrying vehicular traffic across the Monongahela River between Greene and Fayette Counties at Point Marion, Pennsylvania. The form gives its date as 1930 and lists the Pittsburgh & Maines Steel Company as bridge company.","why_significant":"The nomination argues the bridge is unusual as the only Warren through truss and the only cantilever through truss in the nominated group. It is described as an example of the suspended span cantilever truss type, a form widely used in the United States for major river crossings from the late nineteenth century on. The area of significance is engineering.","narrative":"Spanning the Monongahela River at Point Marion, the Marion Bridge links Greene and Fayette Counties in southwestern Pennsylvania. It is a multiple span steel structure of Warren trusses built as a cantilever through truss, with a main span of 464 feet overall and a total length of 810 feet. The bridge dates from 1930 according to the bridge file, and it was built by the Pittsburgh & Maines Steel Company. Its design follows the suspended span cantilever type, in which two outside anchor spans and two cantilever arms support a floating central span. Engineers used this arrangement in the United States from about 1885 to reach distances that simple span trusses could not cover. Its importance rests on engineering: it is the only Warren through truss and the only cantilever through truss in the group nominated under the Commonwealth's highway bridge program. The bridge was altered in 1954, 1961 and 1969.","period_of_significance":null,"architect_builder":null,"architectural_style":null,"criteria":[],"status_note":null,"vacant_flag":null,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:37.89974-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/88000841.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/88000841/b146f9a71c-800.webp","url_1600":"https://nationalhistoricalregister.com/media/88000841/b146f9a71c-1600.webp","licence":"CC BY-SA 3.0","author":"Brian M. Powell (user Bitmapped on en.wikipedia)","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Albert_Gallatin_Memorial_Bridge_(1930_and_2009)_-_Side_View.jpg\" rel=\"noopener\">Brian M. Powell (user Bitmapped on en.wikipedia)</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:Albert_Gallatin_Memorial_Bridge_(1930_and_2009)_-_Side_View.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71992943","wikipedia":"https://en.wikipedia.org/wiki/Albert_Gallatin_Memorial_Bridge","wikidata":"https://www.wikidata.org/wiki/Q4710281"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/fayette-county/marion-bridge-88000841/"}