Airtight Bridge
Also known as: Bridge Number 3165
Why it's listed
Built in 1914 by the Decatur Bridge Company to a design by Claude L. James, this 188-foot steel bridge carries a township road over the Embarras River northeast of Charleston, Illinois. Its main span is an eight-panel Pratt through-truss, pinned and riveted, with a concrete floor, a pony truss approach on the west and a steel beam approach on the east. The site was once known as Willow Pond Ford, and the bridge is the only crossing of the river in the northern half of the county. Local folklore offers two explanations for the name Airtight: stagnant air settling in the surrounding valley, or old cars stalling on the steep eastern hill because of the position of their gasoline tanks. The bridge matters as a clear example of the simple Pratt design, which engineers returned to after earlier bridges added redundant members. It is the newest and simplest of the Embarras River bridges in its group.
Significance in brief: The bridge is the only river crossing in Coles County between Quarry Bridge and the north county line, about 12 miles. It is also a fine example of the simple Pratt truss, showing how early 20th-century engineers returned to a simpler design once steel and better engineering knowledge made extra members unnecessary. It is the newest and simplest bridge in its thematic group.
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 81000211, listed November 30, 1981. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | NE of Charleston, Charleston |
|---|---|
| County | Coles County |
| Listed | November 30, 1981 |
| Reference number | 81000211 |
| Resource type | Structure |
| Architect / builder | Claude L. James (engineer); Decatur Bridge Company, Decatur, IL |
| Architectural style | Pratt through-truss |
| Areas of significance | Engineering, Transportation |
| Level of significance | Local |
| Status (as stated in the nomination) | Described as in fair condition, with a load limit of eight tons. |
| Acreage | 0.9 |
| Coordinates | 39.54913, -88.09330 (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 81000211.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q4699044
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.