Double-Span Metal Pratt Truss Bridge
Why it's listed
Spanning the AuSable River near the southern edge of Keeseville, this wrought-iron bridge links AuSable Street in Clinton County with River Street in Essex County. Built in 1877 by Murray Dougal & Company of Milton, Pennsylvania, to the design of engineer William H. Law, it consists of two identical 107-foot through-truss spans resting on a midstream pier, for a total length of 214 feet and a roadway 16 feet wide. Locally known as the upper bridge, it uses the Pratt configuration, with vertical members in compression and diagonals in tension. The stone pier and abutments have been replaced with concrete, and a steel mesh deck replaced the timber deck in the 1950s. It still carries traffic under a six-ton limit. It is considered the oldest surviving metal Pratt truss bridge in New York State and the earliest metal truss bridge in the Adirondack region. Finials, builder's plates and decorative bracing survive.
Significance in brief: The nomination calls it the oldest surviving metal Pratt truss bridge in New York State and the earliest metal truss bridge in the Adirondack region. It is also a rare surviving example by its manufacturer, Murray Dougal & Company. Its finials, builder's plates and decorative portal bracing remain intact, making it a significant engineering resource and local landmark.
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 83001665, listed May 20, 1983. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence high).
Key facts
| Address | AuSable St., Keeseville |
|---|---|
| County | Clinton County |
| Listed | May 20, 1983 |
| Reference number | 83001665 |
| Resource type | Structure |
| Architect / builder | William H. Law (Engineer); Murray Dougal & Company, Milton, PA |
| Architectural style | Pratt truss (wrought iron, pin-connected) |
| Areas of significance | Engineering |
| Level of significance | Local |
| Status (as stated in the nomination) | Still used as a vehicular bridge, subject to a six-ton limit; condition described as fair. |
| Acreage | 0.9 |
| Coordinates | 44.50034, -73.48499 (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 83001665.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q5299577
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.