{"nrhp_refnum":"72000124","name":"Cooper-Frost-Austin House","other_names":[],"category":"building","location":{"address":"21 Linnaean St.","address_restricted":false,"city":"Cambridge","county":"Middlesex County","state":"MA","lat":42.38445395200006,"lon":-71.12178836299995,"geom_source":"nps_gis"},"listed_date":"1972-09-22","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture"],"significance_levels":["state"],"summary":{"what_it_is":"A two-story, five-bay, center-entrance house at 21 Linnaean Street in Cambridge, Massachusetts, built in two stages between about 1690 and 1720 and owned by a preservation society that operates it as a museum.","why_significant":"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.","narrative":"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.","period_of_significance":"ca. 1690-1720","architect_builder":null,"architectural_style":"Early New England domestic architecture","criteria":[],"status_note":"Listed in good condition, occupied, and used as a museum open to the public; the house stands on its original site.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:11:53.49125-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/20/7956/63795620/content/electronic-records/rg-079/NPS_MA/72000124.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/72000124/c716db7798-800.webp","url_1600":"https://nationalhistoricalregister.com/media/72000124/c716db7798-1600.webp","licence":"CC BY-SA 3.0","author":"Daderot at English Wikipedia","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Cooper-Frost-Austin_House,_Cambridge,_Massachusetts_-_rear.JPG\" rel=\"noopener\">Daderot at English Wikipedia</a>, <a href=\"http://creativecommons.org/licenses/by-sa/3.0/\" rel=\"license noopener\">CC BY-SA 3.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Cooper-Frost-Austin_House,_Cambridge,_Massachusetts_-_rear.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/63795620","wikipedia":"https://en.wikipedia.org/wiki/Cooper%E2%80%93Frost%E2%80%93Austin_House","wikidata":"https://www.wikidata.org/wiki/Q5167733"},"indexable":true,"url":"https://nationalhistoricalregister.com/massachusetts/middlesex-county/cooper-frost-austin-house-72000124/"}