Cooper-Frost-Austin House
Approximate location: the National Park Service places this pin arbitrarily within the property, not at a surveyed point (stated accuracy ±12 m).
Why it's listed
Located at 21 Linnaean Street in Cambridge, this two-story, five-bay house has a center entrance, a steeply pitched roof, a rear lean-to and an attached chaise house, now used as a porch and garage. It was built in stages: the right half around 1690, the left half around 1720, and the lean-to later. Its large pilastered center chimney and overhanging gable are the notable seventeenth-century features, and the interior keeps original fireplaces and exposed framing. The house stands on land owned by Deacon and Selectman John Cooper, whose grandson Walter built the 1720 addition. Later Cooper, Frost and Austin owners were his descendants, and the family held the property until a preservation society acquired it in 1912. It was listed as the oldest complete house in Cambridge and as a well-kept, publicly accessible example of early New England architecture. Some sources date the eastern part to 1657 or 1680.
Significance in brief: The nomination calls it the oldest complete house in Cambridge and the only building in the city that keeps seventeenth-century architectural characteristics. It is also described as a well-preserved, well-maintained example of early New England domestic architecture that is open to the public. It is a certified Massachusetts Historic Landmark.
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 72000124, listed September 22, 1972. Summary generated October 2026 (model claude-sonnet-5-5, prompt v1.0-2026-10-29, confidence medium).
Key facts
| Address | 21 Linnaean St., Cambridge |
|---|---|
| County | Middlesex County |
| Listed | September 22, 1972 |
| Reference number | 72000124 |
| Resource type | Building |
| Period of significance | ca. 1690-1720 |
| Architectural style | Early New England domestic architecture |
| Areas of significance | Architecture |
| Level of significance | State |
| Status (as stated in the nomination) | Listed in good condition, occupied, and used as a museum open to the public; the house stands on its original site. |
| Coordinates | 42.38445, -71.12179 (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 72000124.
- Nomination form (PDF, National Archives) — catalog entry
- Wikipedia article (used for cross-checking only; text not reproduced here)
- Wikidata Q5167733
- This listing as JSON
Last updated October 2026. Found an error? See the editorial policy for how to report it.