McClay's Twin Bridge (East)
Also known as: McClay's Twin Bridge (West)
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Why it's listed
Built in the late 1820s by the master mason Silas Harry, this small stone turnpike bridge carries the road across Conodoquinet Creek near Middle Spring in Franklin County, Pennsylvania. It has two arches of twenty-foot spans and extends 105 feet in total, with a stone parapet topped by a concrete cap. It is one of two camelback bridges Harry built side by side on the same road. Harry was known for stone bridges along the National Road in Pennsylvania and Maryland. Few stone bridges of this kind remain in Franklin County, and the county's bridge historian F. F. Unger documented them. The bridge is valued for its roughly coursed local limestone, its semi-pyramidal piers and its thin limestone coping, features typical of county bridges built before 1860. Its engineering design and construction are the basis for its importance, and it remains in vehicular use after repointing.
Significance in brief: The nomination describes it as a very fine example of a small, multiple-span nineteenth-century turnpike bridge built by Silas Harry, a master mason known for stone bridges along the National Road in Pennsylvania and Maryland. Few stone bridges of its kind in Franklin County survive, and its roughly coursed local limestone, semi-pyramidal piers and thin limestone coping are typical of county bridges built before 1860.
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 88000777, listed June 22, 1988. Summary generated October 2026 (model claude-haiku-5-5, prompt v1.1-2026-10-29, confidence medium).
Key facts
| Address | LR 28010 over trib. to Conodoguinet Creek, Middle Spring |
|---|---|
| County | Franklin County |
| Listed | June 22, 1988 |
| Reference number | 88000777 |
| Resource type | Structure |
| Period of significance | 1827-1829 |
| Architect / builder | Silas Harry (builder) |
| Architectural style | Camelback |
| Areas of significance | Engineering |
| Level of significance | State |
| Status (as stated in the nomination) | Repointed; in vehicular use |
| Acreage | 0.9 |
| Coordinates | 40.09852, -77.57068 (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 88000777.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q15252508
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.