Duncan Mills Bridge
Why it's listed
Duncan Mills Bridge is a single-span steel highway bridge in Isabelle Township, about a quarter mile west of the Illinois 78/97 route near Lewistown in Fulton County, Illinois. Built around 1910 and manufactured by the Illinois Steel Bridge Company of Jacksonville, it is a Parker through truss with a bottom chord of double eyebars, a concrete deck and stone piers. Its chord length is recorded as about 177 feet. The engineer is unknown. The bridge was included as one of several surviving metal truss bridges in a county-wide group dating from 1883 to 1915. Together these bridges show how Fulton County improved its highway system by replacing earlier bridges with modern steel trusses. They also illustrate changes in steel bridge construction, including Pratt and Parker designs, over about 35 years. The bridge was evaluated as significant at the state level.
Significance in brief: The bridge is one of a thematic group of metal highway bridges in Fulton County that survive from the late 19th and early 20th centuries. The group reflects the county's replacement of early bridges with up-to-date steel trusses and shows variations in steel bridge construction, including Pratt and Parker types. It was evaluated as significant at the state level.
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 80001356, listed October 29, 1980. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | W of Havanna, Lewistown |
|---|---|
| County | Fulton County |
| Listed | October 29, 1980 |
| Reference number | 80001356 |
| Resource type | Structure |
| Architect / builder | Illinois Steel Bridge Company, Jacksonville, Illinois (manufacturer); engineer unknown |
| Architectural style | Parker truss |
| Areas of significance | Engineering, Transportation |
| Level of significance | State |
| Acreage | 0.9 |
| Coordinates | 40.34063, -90.18946 (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 80001356.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q5314541
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.