House at 170 Otis Street
Why it's listed
Built in 1870-71 on a wooded hillside in Newtonville, this two-story mansard house was designed by Boston architect Hammatt Billings, whose work also includes the Boston Museum and the original Wellesley College buildings. His watercolor elevation and floor plans, dated September 1869, remain in the house. Its most striking feature is a 2-1/2-story mansard tower on the west facade, with original iron cresting and slate fishscale shingles. Flanking pavilions, segmental windows with carved bosses, and Eastlake-inspired brackets add ornament. William Claflin, a real estate developer who served as Governor of Massachusetts beginning in 1869, had it built for his daughter Emma and her husband, Charles Warren Ellis. Later occupants included Boston dry goods merchant George L. Clark and, from the 1890s, the family of paper wholesaler J. Richard Carter, who kept the house until the 1950s. The house is valued as an example of the mansard style and for its Claflin connection.
Significance in brief: The house is an important example of the mansard style in Newton by the nationally known architect Hammatt Billings, one of few known Newton works by him. It is also associated with the Claflin family, as it was built for the daughter of Governor William Claflin and her husband.
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 86001819, listed September 4, 1986. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence high).
Key facts
| Address | 170 Otis St., Newton |
|---|---|
| County | Middlesex County |
| Listed | September 4, 1986 |
| Reference number | 86001819 |
| Resource type | Building |
| Architect / builder | Hammatt Billings |
| Architectural style | Mansard |
| Criteria |
|
| Areas of significance | Commerce, Architecture, Social History |
| Level of significance | State, Local |
| Status (as stated in the nomination) | Described as in good condition, retaining its iron cresting; a deck and north chimney were added and windows in the south ell were altered. |
| Acreage | 1.2 |
| Coordinates | 42.34622, -71.21471 (NPS GIS) |
What listing means for this property
National Register listing is honorary for a privately owned home: it does not by itself restrict what an owner may do with their own money, and it does not require public access. Restrictions come from local landmark or historic-district ordinances, which are separate (how they differ).
Owner-occupied houses are not eligible for the 20% federal rehabilitation tax credit, which applies to income-producing buildings, but many states offer credits for homeowners. Listing also opens the door to preservation easements and to buying a plaque. Start with what listing means for homeowners, renovating a listed house and selling one.
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 86001819.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q5913991
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.