Urban Rowhouse
Why it's listed
Four connected brick rowhouses at 26-32 River Street in Cambridgeport were erected in 1860 by Frederick Clapp, a Boston woodenware dealer, who lived in No. 26. Faced with pressed brick and trimmed in brownstone, they follow the Mansard style, with a slate roof, pedimented dormers and symmetrical design. Their facades are staggered to fit an irregular lot, and their design is comparable to rowhouses of the same date in Boston's South End. Some trim that looks like brownstone is actually wood, painted and dusted with sand as an economy measure. After horse car service to Boston began in 1853, Cambridgeport attracted Boston merchants, and these houses are the only Cambridge examples of early bell-cast Mansard houses built in quantity elsewhere around Boston. Three houses remain in original condition, while No. 26 has store windows that are considered recoverable. Together they form a monumental streetscape that marks the urbanization of a once rural village.
Significance in brief: The rowhouses are described as the most elaborate early examples of their type remaining in Cambridge and the only Cambridge representatives of early bell-cast Mansard houses. They embody Second Empire urban residential construction, with a slate mansard roof, pedimented dormers and brownstone trim. Their staggered facades fit an irregular lot and reflect the growing urbanization of Cambridgeport.
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 83000831, listed June 30, 1983. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | 26-32 River St., Cambridge |
|---|---|
| County | Middlesex County |
| Listed | June 30, 1983 |
| Reference number | 83000831 |
| Resource type | Building |
| Architect / builder | Anonymous architect; built for Frederick Clapp |
| Architectural style | Mansard (Second Empire) |
| Criteria |
|
| Areas of significance | Architecture |
| Level of significance | Local |
| Status (as stated in the nomination) | Three of the four houses are in original condition; No. 26 has store windows inserted, alterations described as recoverable. Present use is residential/commercial. |
| Acreage | 0.9 |
| Coordinates | 42.36467, -71.10582 (NPS GIS) |
What listing means for this property
National Register listing is honorary: it recognises significance and does not restrict what a private owner may do without federal money or permits. It unlocks the 20% federal rehabilitation tax credit for income-producing buildings, state credits in many states, and Section 106 review when federal agencies are involved. See what listing means in practice.
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 83000831.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q7900005
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.