Ehrhart's Mill Historic District
Why it's listed
Along Old Mill Road beside Saucon Creek in Lower Saucon Township stands a cluster of nineteenth-century buildings centred on a limestone grist mill. The mill, rebuilt after a fire in 1865 under a gambrel roof, still holds three runs of mill stones, a 42-inch turbine that replaced an earlier water wheel around 1900, and most of its nineteenth-century milling machinery, which is rare among surviving local mills. The district also includes a mill house, a brick retirement house, a limestone farmhouse of about 1850, outbuildings, and an iron Pratt truss bridge completed in 1867. Its significance rests on that bridge, regarded as the earliest known iron Pratt truss bridge in Pennsylvania and a forerunner of a design later used widely across the state, and on the mill's unusually complete equipment. The houses, built by members of one family, are a locally notable mix of stone and brick construction.
Significance in brief: The grist mill is described as the largest late-nineteenth and early twentieth century grist mill on Saucon Creek and the only one in southern Northampton County that retains all its nineteenth century milling equipment. County Bridge #16, an iron Pratt truss bridge erected in 1867, is described as the earliest known iron Pratt truss bridge in Pennsylvania. The district also holds locally important rural architecture.
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 87000666, listed April 30, 1987. Summary generated October 2026 (model claude-haiku-5-5, prompt v1.1-2026-10-29, confidence high).
Key facts
| Address | Old Mill Rd., Hellertown |
|---|---|
| County | Northampton County |
| Listed | April 30, 1987 |
| Reference number | 87000666 |
| Resource type | District |
| Period of significance | 1800-1937 |
| Criteria |
|
| Areas of significance | Commerce, Engineering, Architecture |
| Level of significance | State |
| Status (as stated in the nomination) | The bridge has been closed to vehicular traffic since 1983 after a beam cracked, and the district is described as endangered by a township plan to demolish the bridge. |
| Acreage | 5.2 |
| Coordinates | 40.56197, -75.34897 (NPS GIS) |
What listing means for this property
This is a historic district. Buildings within its boundary are either contributing (they add to the district's significance) or non-contributing. Owners of contributing income-producing buildings can claim the 20% federal rehabilitation tax credit; homeowners should look at state credits. National Register districts impose no design review by themselves; a local historic district ordinance, if one exists, does (the difference explained).
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 87000666.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q5348621
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.