South Washington Street Parabolic Bridge
Why it's listed
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.
Significance in brief: 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.
Machine-generated summary. This summary was generated by a language model from the official nomination document and has not been reviewed line by line by an editor. It may contain errors. Check the source document before relying on any detail. Source: nomination document (PDF) · National Archives catalog entry. NRHP reference 78001842, listed January 30, 1978. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence high).
Key facts
| Address | S. Washington St., Binghamton |
|---|---|
| County | Broome County |
| Listed | January 30, 1978 |
| Reference number | 78001842 |
| Resource type | Structure |
| Period of significance | 1800-1899 (specific dates 1886-1887) |
| Architect / builder | Berlin Iron Bridge Company |
| Areas of significance | Engineering, Transportation |
| Level of significance | State |
| Status (as stated in the nomination) | 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. |
| Acreage | 1 |
| Coordinates | 42.09259, -75.91475 (NPS GIS) |
What listing means for this property
For a publicly owned building or structure, listing mainly matters when federal funds, permits or licences are involved: projects then go through Section 106 review so effects on the property are considered. Listing also strengthens applications for preservation grants and, for leased income-producing uses, can enable the federal rehabilitation tax credit.
General information, not legal or tax advice. Rules change; confirm with your State Historic Preservation Office or a qualified adviser.
Sources and further reading
- National Park Service, National Register of Historic Places database (snapshot May 2026), reference 78001842.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q7568808
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.