{"nrhp_refnum":"70000547","name":"Leiper, Thomas, Estate","other_names":["Avondale"],"category":"building","location":{"address":"Avondale Rd.","address_restricted":false,"city":"Wallingford","county":"Delaware County","state":"PA","lat":39.886688004000064,"lon":-75.35798457799996,"geom_source":"nps_gis"},"listed_date":"1970-12-29","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Architecture"],"significance_levels":["national"],"summary":{"what_it_is":"The Thomas Leiper Estate is a group of 18th-century buildings in Wallingford, Delaware County, Pennsylvania, centered on a three-storey yellow stuccoed mansion house dated 1785, with outbuildings including stone barns, snuff mills, a springhouse, a drying house and a log house.","why_significant":"The nomination argues the estate is a rare and nearly intact small eighteenth-century community built around the industrial and manufacturing activities of Thomas Leiper, a patriot, inventor and merchant. It cites the relatively unchanged Crum Creek site with its workmen's cottages, dam, mill, quarry and outbuildings, and the deliberate architectural design of the house and grounds in relation to its surroundings.","narrative":"Built in 1785 on a hill above Crum Creek Valley in Wallingford, the three-storey yellow stuccoed mansion stands with a range of stone outbuildings, including barns, a springhouse, two snuff mills, a drying house, a log house and a smith shop. It was the home of Thomas Leiper, born in Scotland in 1745, who arrived in America in 1764 and built a fortune in the tobacco and snuff trade. In 1776 he bought land in Nether Providence Township and set up two snuff mills, and in 1809 he built a railroad to carry stone from his quarries to Ridley Creek, which the document describes as the first permanent railroad in the United States. The house is distinguished by its planning: a granite-railed drive leads to a pedimented entrance, a basement door connects the office to a vault in a fireproof outbuilding, and first-floor windows open into doors. The estate is valued for its largely unchanged industrial and architectural setting.","period_of_significance":"1785","architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Condition is marked good and unaltered at original site; the document notes the estate was endangered by plans for the Midcounty Expressway.","vacant_flag":null,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:30.146009-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/70000547.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/70000547/b62df35666-800.webp","url_1600":"https://nationalhistoricalregister.com/media/70000547/b62df35666-1600.webp","licence":"CC0","author":"Smallbones","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Thomas_Leiper_House_Delco_PA.jpg\" rel=\"noopener\">Smallbones</a>, <a href=\"http://creativecommons.org/publicdomain/zero/1.0/deed.en\" rel=\"license noopener\">CC0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Thomas_Leiper_House_Delco_PA.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71998497","wikipedia":"https://en.wikipedia.org/wiki/Thomas_Leiper_Estate","wikidata":"https://www.wikidata.org/wiki/Q7791803"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/delaware-county/leiper-thomas-estate-70000547/"}