{"nrhp_refnum":"83000831","name":"Urban Rowhouse","other_names":[],"category":"building","location":{"address":"26-32 River St.","address_restricted":false,"city":"Cambridge","county":"Middlesex County","state":"MA","lat":42.36466638600007,"lon":-71.10582095699993,"geom_source":"nps_gis"},"listed_date":"1983-06-30","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture"],"significance_levels":["local"],"summary":{"what_it_is":"A row of four brick Mansard-style urban rowhouses at 26-32 River Street in Cambridgeport, Cambridge, Massachusetts, built in 1860 for Frederick Clapp, a Boston woodenware dealer. The architect is anonymous.","why_significant":"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.","narrative":"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.","period_of_significance":null,"architect_builder":"Anonymous architect; built for Frederick Clapp","architectural_style":"Mansard (Second Empire)","criteria":["C"],"status_note":"Three of the four houses are in original condition; No. 26 has store windows inserted, alterations described as recoverable. Present use is residential/commercial.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:11:56.702314-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/75/7904/63790475/content/electronic-records/rg-079/NPS_MA/83000831.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/83000831/adffedf043-800.webp","url_1600":"https://nationalhistoricalregister.com/media/83000831/adffedf043-1600.webp","licence":"CC BY-SA 3.0","author":"Tim Pierce","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Urban_Rowhouse_26-32_River_St.jpg\" rel=\"noopener\">Tim Pierce</a>, <a href=\"https://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:Urban_Rowhouse_26-32_River_St.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/63790475","wikipedia":"https://en.wikipedia.org/wiki/Urban_Rowhouse_(26%E2%80%9332_River_Street,_Cambridge,_Massachusetts)","wikidata":"https://www.wikidata.org/wiki/Q7900005"},"indexable":true,"url":"https://nationalhistoricalregister.com/massachusetts/middlesex-county/urban-rowhouse-83000831/"}