{"nrhp_refnum":"78001842","name":"South Washington Street Parabolic Bridge","other_names":[],"category":"structure","location":{"address":"S. Washington St.","address_restricted":false,"city":"Binghamton","county":"Broome County","state":"NY","lat":42.09259428000007,"lon":-75.91475296599998,"geom_source":"nps_gis"},"listed_date":"1978-01-30","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"A three-span iron lenticular (\"parabolic\") truss bridge carrying South Washington Street over the Susquehanna River in Binghamton, Broome County, New York, built in 1886-1887 and owned by the city.","why_significant":"It is described as the longest multiple-span lenticular truss bridge built in New York State in the nineteenth century. It incorporates the \"parabolic\" truss design patented by Binghamton engineer William O. Douglas and was fabricated by the Berlin Iron Bridge Company. Its rarity, large scale and link to Douglas and Binghamton underpin its engineering and historical importance.","narrative":"Spanning the Susquehanna River in Binghamton, this three-span iron bridge carried South Washington Street traffic from its completion in 1886-1887 until 1969. Fabricated by the Berlin Iron Bridge Company of Connecticut at a cost of $38,000, it uses the lenticular, or \"parabolic,\" truss patented by Binghamton engineer William O. Douglas, a Civil War veteran who assigned his patents to the firm. Three identical trusses give an overall length of 484 feet, resting on stone abutments and piers. The bridge replaced an obsolete wooden covered bridge and later carried an electric streetcar line and crowds heading to Ross Park. It is considered the longest multiple-span lenticular truss bridge built in New York State in the nineteenth century, and such bridges have become increasingly rare. Salt-related damage to the deck supports closed it to vehicles in 1969, and it now serves pedestrians only.","period_of_significance":"1800-1899 (specific dates 1886-1887)","architect_builder":"Berlin Iron Bridge Company","architectural_style":null,"criteria":[],"status_note":"Closed to vehicles in 1969 because of deck support deterioration from road salt; used only by pedestrians since then. The form describes its future as uncertain.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:50:39.973248-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_NY/78001842.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/78001842/f99cff7bf4-800.webp","url_1600":"https://nationalhistoricalregister.com/media/78001842/f99cff7bf4-1600.webp","licence":"CC BY-SA 3.0","author":"Jtpurdom","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:BingSWashingtonBridge.JPG\" rel=\"noopener\">Jtpurdom</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:BingSWashingtonBridge.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/75316610","wikipedia":"https://en.wikipedia.org/wiki/South_Washington_Street_Parabolic_Bridge","wikidata":"https://www.wikidata.org/wiki/Q7568808"},"indexable":true,"url":"https://nationalhistoricalregister.com/new-york/broome-county/south-washington-street-parabolic-bridge-78001842/"}