{"nrhp_refnum":"04000775","name":"Milliken Creek Bridge","other_names":["Bridge No. 21C-51"],"category":"structure","location":{"address":"Trancas St. across Milliken Creek","address_restricted":false,"city":"Napa","county":"Napa County","state":"CA","lat":38.325372912000034,"lon":-122.27405662599995,"geom_source":"nps_gis"},"listed_date":"2004-08-05","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["local"],"summary":{"what_it_is":"A five-span stone arch highway bridge, 169 feet long and about 26 feet wide, carrying Trancas Street (Trancas Road) over Milliken Creek in Napa, California. It was designed in 1908 by Oliver H. Buckman and built by contractor H. W. Wing.","why_significant":"The bridge is significant under Criterion C in the area of Engineering as an example of early twentieth century stone masonry arch bridge construction. Stone masonry bridges are a rare type in California, built mostly in Napa County, and most were lost or heavily altered. This bridge retains integrity and is one of the two or three longest unaltered stone masonry bridges in the state.","narrative":"Milliken Creek Bridge carries Trancas Street over Milliken Creek in Napa. Built in 1908, it is a stone arch structure 169 feet long and about 26 feet wide, with five segmental arches of locally quarried rock, probably trachytic tuff, laid as pitch-faced ashlar. The center span and the span next to it on the east are 40 feet long; the others are 20 feet. Oliver H. Buckman, Napa County Surveyor from about 1900 to about 1915, designed it, and H. W. Wing, a well-known local stone mason, was the contractor. Stone masonry bridges are rare in California and were built mainly in Napa County, where many have disappeared and most survivors were severely altered. This one has only an asphalt layer added to the deck, which now carries one lane. Its length made it an unusually ambitious project for the county, and today it is among the longest unaltered stone masonry bridges in the state. It was listed for its engineering significance.","period_of_significance":"1908","architect_builder":"Buckman, Oliver H. (designer); Wing, H. W. (contractor)","architectural_style":"Other: Stone Arch Bridge","criteria":["C"],"status_note":"Still used for road traffic, now with a single lane and an asphalt deck; a newer bridge about 100 feet north carries most local traffic. The structure appears unaltered apart from the asphalt.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:54:29.606757-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/04000775.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/04000775/0ad7db4a13-800.webp","url_1600":"https://nationalhistoricalregister.com/media/04000775/0ad7db4a13-1600.webp","licence":"CC BY-SA 3.0","author":"Sanfranman59","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Milliken_Creek_Bridge,_Trancas_St.,_Napa,_CA_9-5-2010_1-19-32_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:Milliken_Creek_Bridge,_Trancas_St.,_Napa,_CA_9-5-2010_1-19-32_PM.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123857694","wikipedia":null,"wikidata":"https://www.wikidata.org/wiki/Q133308021"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/napa-county/milliken-creek-bridge-04000775/"}