Charleroi-Monessen Bridge
Why it's listed
Built in 1906 by the Mercantile Bridge Company from a design by engineer Emil Swensson, the Charleroi-Monessen Bridge carries vehicular traffic across the Monongahela River, connecting the town of Charleroi with factories on the opposite bank. It is a steel structure with three Pennsylvania (Petit) truss spans of about 400 feet each, the anchor span among them, and thirteen deck girder spans. The total length is about 2,458 feet. The truss spans are pin-connected and riveted, with loop-welded or die-forged eyebars, and the abutments are coursed ashlar. The bridge is regarded as a good example of its type. Its combination of long truss spans and a large number of girder approaches made it one of the longest bridges in its group. Its location in southwestern Pennsylvania, an area with many truss bridges, adds to its importance in the state's engineering history.
Significance in brief: The nomination describes it as a good example of a multiple-span Pennsylvania (Petit) truss bridge. It combines three longer Pennsylvania truss spans with thirteen deck girder spans, making it one of the longest bridges in its thematic group. It lies in southwestern Pennsylvania, an area with a heavy concentration of truss bridges, and its significance is placed under engineering.
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 88000812, 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 247 over Monongahela River, Charleroi |
|---|---|
| County | Washington County |
| Listed | June 22, 1988 |
| Reference number | 88000812 |
| Resource type | Structure |
| Period of significance | 1906 |
| Architect / builder | Emil Swensson (engineer); Mercantile Bridge Company (bridge company) |
| Criteria |
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| Areas of significance | Engineering |
| Level of significance | State |
| Acreage | 0.9 |
| Coordinates | 40.15186, -79.90389 (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 88000812.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q5074682
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.