{"nrhp_refnum":"05000781","name":"Napa River Bridge on Zinfandel Lane","other_names":["Bridge no. 21CO002"],"category":"structure","location":{"address":"Zinfandel Ln., 1 mi. E of CA 29","address_restricted":false,"city":"St. Helena","county":"Napa County","state":"CA","lat":38.495519940000065,"lon":-122.54057193999995,"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 two-span masonry arch road bridge carrying Zinfandel Lane over the Napa River, about one mile east of State Highway 29 near St. Helena, Napa County, California. It was built in 1913 from a design by Napa County's surveyor and engineer, with J.B. Newman as contractor.","why_significant":"The bridge is a well-preserved example of a stone masonry arch, a rare bridge type in California. It reflects Napa County's continued use of stone bridges into the early twentieth century, helped by a county engineer who favored stone, nearby quarries and skilled immigrant masons. It retains integrity of design, setting, materials and workmanship.","narrative":"Carrying Zinfandel Lane across the Napa River about a mile east of State Highway 29, this two-lane bridge is an earth-filled, closed-spandrel masonry arch built in 1913. It has two spans of 43 feet each, measures 95 feet long and 23.5 feet wide, and is made of square-cut stone laid in regular courses, with cut-stone railings. Trees and fields surround it. Napa County Surveyor O.H. Buckman designed the bridge, and contractor J.B. Newman built it for $5,450. Napa County kept building stone arch bridges into the early twentieth century, long after most of California had turned to metal trusses, thanks to Buckman's confidence in stone, good local quarries and skilled stonemasons. The bridge was recognized for its engineering as a fine example of a rare bridge type in California. It has seen only routine maintenance, apart from minor parapet damage, and keeps its original look and rural setting. It remains in use as a public road crossing.","period_of_significance":"1913","architect_builder":"Buckam, O.H. (designer); Newman, J.B. (contractor)","architectural_style":"Other: Masonry Arch Bridge","criteria":["C"],"status_note":"Still in vehicular use; appears essentially unaltered with only routine maintenance, though a small section of the northwest parapet has been knocked down and the center pier base has a concrete slab around it.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:54:29.660413-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/05000781.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/05000781/12a4328ce0-800.webp","url_1600":"https://nationalhistoricalregister.com/media/05000781/12a4328ce0-1600.webp","licence":"CC BY-SA 3.0","author":"Sanfranman59","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Napa_River_Bridge_on_Zinfandel_Lane,_St._Helena,_CA_10-9-2011_5-36-22_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:Napa_River_Bridge_on_Zinfandel_Lane,_St._Helena,_CA_10-9-2011_5-36-22_PM.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123857696","wikipedia":null,"wikidata":"https://www.wikidata.org/wiki/Q133308704"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/napa-county/napa-river-bridge-on-zinfandel-lane-05000781/"}