{"nrhp_refnum":"91001135","name":"Isabella Furnace","other_names":[],"category":"district","location":{"address":"Bollinger Dr. just N of Creek Rd., Nantmeal Township","address_restricted":false,"city":"Brandywine Manor","county":"Chester County","state":"PA","lat":40.11342712700008,"lon":-75.82280946599997,"geom_source":"nps_gis"},"listed_date":"1991-09-06","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Industry"],"significance_levels":["state"],"summary":{"what_it_is":"Isabella Furnace is an iron furnace complex in a wooded valley on Perkins Run, a tributary of the East Branch of the Brandywine Creek, southwest of Elverson in Chester County, Pennsylvania. The complex includes a charcoal house, machine shop/blacksmith shop, charging ramp and furnace stack ruin, engine house, wheel house, and a stone arch bridge.","why_significant":"The nomination argues the furnace is significant under Criterion A for industry because it was one of the longest-running iron furnace complexes in eastern Pennsylvania, operating from 1835 to 1894 and among the last built in Chester County. It is also argued to be significant under Criterion C for engineering, particularly its stone arch railroad bridge, which is described as having no other known example of its type in Pennsylvania.","narrative":"Built in 1835 by Henry Potts and John P. Rutter on forty-nine acres that already held a sawmill and a fulling mill, Isabella Furnace was an iron-smelting complex on Perkins Run in Chester County. David Potts managed the furnace from 1836 and secured ore from the St. Peter's and St. Mary's mines. After a sale in 1856 to John Irey and James Butler, and later to the Smith brothers in 1864, Col. Joseph Potts reacquired it by 1880, converting the hot blast drive to steam power and building a brick engine house. A narrow gauge siding from the Pennsylvania Railroad's Downingtown branch reached the site. The furnace closed in 1894, when it had ceased to be profitable. Its significance lies in its long operating life, its late construction in the county, and a stone arch railroad bridge that carried rail cars into the charcoal house.","period_of_significance":"1835-1894","architect_builder":null,"architectural_style":null,"criteria":["A"],"status_note":"Furnace stack collapsed several years ago; roofs, trussing and machinery were removed and sold for scrap in 1944; a swimming pool was built c. 1975 and is non-contributing.","vacant_flag":null,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:37.829703-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/91001135.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/91001135/066231f00d-800.webp","url_1600":"https://nationalhistoricalregister.com/media/91001135/066231f00d-1600.webp","licence":"Public domain","author":"Ned Goode HABS photographer","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Isabella_HABS_132492pu.jpg\" rel=\"noopener\">Ned Goode HABS photographer</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Isabella_HABS_132492pu.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71992714","wikipedia":"https://en.wikipedia.org/wiki/Isabella_Furnace","wikidata":"https://www.wikidata.org/wiki/Q6077990"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/chester-county/isabella-furnace-91001135/"}