{"nrhp_refnum":"85001004","name":"Harlan House","other_names":["Star Gazers House","Star Gazer Farm"],"category":"building","location":{"address":"PA 162 and Star Gazer Rd.","address_restricted":false,"city":"Embreeville","county":"Chester County","state":"PA","lat":39.93826511450007,"lon":-75.7319331667147,"geom_source":"nps_gis"},"listed_date":"1985-05-09","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Exploration/Settlement","Science","Architecture"],"significance_levels":["state"],"summary":{"what_it_is":"A farmhouse with a stone dwelling and a newly built frame barn, located at the corner of Route 162 and Star Gazer Road near Embreeville in south-central Chester County, Pennsylvania. The property also includes the Star Gazers' Stone, a marker set in a field about 700 feet north of the house.","why_significant":"The house is argued to be an excellent example of early 18th-century Colonial vernacular masonry architecture, with its walk-in cooking fireplace a notable feature. The site is significant because Mason and Dixon used a temporary observatory near the house in 1764-68 to survey the Pennsylvania-Maryland boundary, later known as the Mason-Dixon Line, which contributed to surveying methods and knowledge of the earth's size and shape.","narrative":"Set in the rolling hills near the Brandywine Creek, this farmhouse dates to about 1724 and was built as a fieldstone two-bay core, with a stone addition of about 1758 and a 19th-century frame wing. The addition retains its original double fireplace, including a walk-in cooking hearth with a flagstone floor, a crane and an oak lintel, which the document describes as the most notable feature of the house. Its masonry construction is considered a rare and accomplished example of mid-18th-century vernacular building among the homes of Quaker and Scotch-Irish settlers in southern Chester County. The Harlan family lived here until 1956. Its importance also lies in the 1764 to 1768 stay of the astronomers Charles Mason and Jeremiah Dixon, who set up a temporary observatory here. From a point north of the house they measured an arc of meridian used to survey the boundary between Pennsylvania and Maryland. The marker they left, the Star Gazers' Stone, is still in a field 700 feet north of the house.","period_of_significance":"1724-1768","architect_builder":null,"architectural_style":"Colonial vernacular","criteria":["A","C"],"status_note":"The house was the Harlan family residence until 1956; the document does not state its current condition or use.","vacant_flag":null,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:13:22.576067-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/85001004.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/85001004/c5cd4a877a-800.webp","url_1600":"https://nationalhistoricalregister.com/media/85001004/c5cd4a877a-1600.webp","licence":"Public domain","author":"Smallbones at en.wikipedia","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Stargazers_Stone.jpg\" rel=\"noopener\">Smallbones at en.wikipedia</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Stargazers_Stone.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71995457","wikipedia":"https://en.wikipedia.org/wiki/Star_Gazers%27_Stone","wikidata":"https://www.wikidata.org/wiki/Q7600726"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/chester-county/harlan-house-85001004/"}