{"nrhp_refnum":"05000780","name":"Swartz Creek Bridge on Aetna Springs Road","other_names":[],"category":"structure","location":{"address":"Aetna Springs Rd., 0.8 mi. W of Pope Valley Rd.","address_restricted":false,"city":"Aetna Springs","county":"Napa County","state":"CA","lat":38.65331898800008,"lon":-122.47658436999996,"geom_source":"nps_gis"},"listed_date":"2005-08-05","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["local"],"summary":{"what_it_is":"A single-span masonry arch road bridge carrying Aetna Springs Road over Swartz Creek, about 0.8 miles west of Pope Valley Road in Napa County, California. It was built in 1912.","why_significant":"The bridge is a fine, essentially unaltered example of a rare masonry arch bridge type in California and meets the registration requirements for masonry arch bridges in the state's historic highway bridges listing. It was designed by Napa County Surveyor O.H. Buckman, whose designs account for the many stone arch bridges in the county. It is significant locally in the area of engineering under Criterion C.","narrative":"Carrying Aetna Springs Road over Swartz Creek in a rural setting of trees and fields, this 1912 bridge is a single 42-foot span, earth-filled, closed-spandrel masonry arch. It is 54 feet long and 19.5 feet wide, with two lanes. Both the arch and the railings are built of square-cut stone laid in irregular courses. Napa County Surveyor O.H. Buckman designed it, and contractor A.C. Martini built it for $2,549.50. Napa County built many such stone bridges in the late nineteenth and early twentieth centuries, helped by nearby high-quality building stone and skilled stonemasons. Maintenance records show only routine upkeep, and the bridge keeps its original appearance and setting. It was listed for its engineering significance at the local level, as a rare and unaltered example of a masonry arch bridge in California. It continues to serve vehicle traffic and is owned by the County of Napa.","period_of_significance":"1912","architect_builder":"Buckman, O.H. (designer); Martini, A.C. (contractor)","architectural_style":"Other: Masonry Arch Bridge","criteria":["C"],"status_note":"Still in use as a road bridge; the structure appears essentially unaltered, with only routine maintenance since 1912.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:54:29.435781-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/05000780.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/05000780/0135e715a6-800.webp","url_1600":"https://nationalhistoricalregister.com/media/05000780/0135e715a6-1600.webp","licence":"CC BY-SA 3.0","author":"Sanfranman59","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Swartz_Creek_Bridge_on_Aetna_Springs_Road,_Aetna_Springs,_CA_10-22-2011_4-30-43_PM.JPG\" rel=\"noopener\">Sanfranman59</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:Swartz_Creek_Bridge_on_Aetna_Springs_Road,_Aetna_Springs,_CA_10-22-2011_4-30-43_PM.JPG"},"district":{"nrhp_refnum":"87000341","name":"Aetna Springs Resort","url":"https://nationalhistoricalregister.com/districts/california/aetna-springs-resort-87000341/"},"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123857698","wikipedia":"https://en.wikipedia.org/wiki/Swartz_Creek_Bridge_on_Aetna_Springs_Road","wikidata":"https://www.wikidata.org/wiki/Q85804436"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/napa-county/swartz-creek-bridge-on-aetna-springs-road-05000780/"}