Hopkinton Dam and Spillway
Why it's listed
Built between 1891 and 1894 across Indian Brook, this dam and spillway sit in Hopkinton State Park in the southwest corner of Ashland. The dam is an earthen embankment with a concrete core wall resting on bedrock, plastered with Portland cement on the upstream side and faced with granite blocks. At its west end, a 30-foot overfall leads into a 650-foot spillway that descends through a series of granite-paved steps with rounded granite coping, giving the look of a brook running through the woods. The structure was one of the later additions to the Sudbury River supply and storage system, which began in the 1870s and also includes the Framingham Reservoirs and the Sudbury Aqueduct. Two gate chambers once fed an overflow channel and filter beds, which have since been removed and replaced by a sandy beach. The dam and spillway are valued for their link to Boston's metropolitan water supply and for their late nineteenth century engineering and design.
Significance in brief: The dam and spillway are tied to the Sudbury River water supply, the second source tapped by the Metropolitan Water Board. They are good examples of late 19th century water technology and design. The granite spillway is called particularly outstanding for its sculptural, stream-like appearance.
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 89002288, listed January 18, 1990. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | E end of Hopkinton Reservoir in Hopkinton State Park, Ashland |
|---|---|
| County | Middlesex County |
| Listed | January 18, 1990 |
| Reference number | 89002288 |
| Resource type | Structure |
| Criteria |
|
| Areas of significance | Community Planning and Development, Engineering, Politics/Government |
| Level of significance | State, Local |
| Status (as stated in the nomination) | Condition is described as good. The dam and spillway were removed from water-supply service when the reservoir was turned over to the Commonwealth for use as a state park. |
| Acreage | 15 |
| Coordinates | 42.25644, -71.51087 (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 89002288.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q5900778
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.