Whipple Cast and Wrought Iron Bowstring Truss Bridge
Why it's listed
Spanning a deep ravine at Normanskill Farm in Albany, this iron bridge is a Whipple bowstring truss with a free span of 109 feet, 10 inches. Each top chord is an arch of nine cast-iron segments working in compression, while wrought-iron links in the bottom chords restrain the arch's outward thrust. Sixteen vertical iron rods carry the load upward, and a deck of iron beams supports diagonal wood planking. Simon DeGraft of Syracuse fabricated it in 1867, and its original location is unknown. When the Albany and Delaware Turnpike, now Delaware Avenue, was rerouted in 1899, the farm bought the bridge and re-erected it over the ravine separating the property from the new highway. The design came from Squire Whipple, who patented his iron bowstring truss in 1841. The bridge is regarded as one of the earliest surviving iron bridges in the United States and remains the farm's main entrance.
Significance in brief: The bridge is a surviving example of the Whipple bowstring truss, designed by Squire Whipple, one of the earliest civil engineers to develop a scientific basis for American bridge building. It is described as one of the earliest surviving iron bridges in the United States and a key landmark in American civil engineering history. It is still in use as the farm's main entrance.
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 71000523, listed March 18, 1971. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence high).
Key facts
| Address | 1000 Delaware Ave., Albany |
|---|---|
| County | Albany County |
| Listed | March 18, 1971 |
| Reference number | 71000523 |
| Resource type | Structure |
| Period of significance | 19th Century (specific date 1867) |
| Architect / builder | Simon DeGraft of Syracuse, New York (builder); Whipple truss design by Squire Whipple |
| Areas of significance | Commerce, Engineering, Transportation, Invention |
| Level of significance | State |
| Status (as stated in the nomination) | Described as well maintained, in good condition, and still serving as the main entrance to Normanskill Farm. |
| Within district | Normanskill Farm |
| Coordinates | 42.63575, -73.80066 (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 71000523.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q7993745
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.