{"nrhp_refnum":"05000777","name":"Maxwell Creek Bridge on Hardin Road","other_names":["Bridge No. 21CO58"],"category":"structure","location":{"address":"Hardin Rd., 1.6 mi. SE of Pope Canyon Rd.","address_restricted":false,"city":"Locoallomi","county":"Napa County","state":"CA","lat":38.601521956000056,"lon":-122.37119302399998,"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, earth-filled masonry arch road bridge carrying Hardin Road over Maxwell Creek, 1.6 miles southeast of Pope Canyon Road in Napa County, California. It was built in 1909 and designed by County Surveyor O.H. Buckman.","why_significant":"The bridge is significant under Criterion C in the area of engineering, at the local level, as an unaltered example of a masonry arch bridge, a rare bridge type in California. It reflects Napa County's continued use of stone arch construction into the early twentieth century, supported by a county surveyor who favored stone, good local stone and skilled masons. It retains a high degree of integrity of design and setting.","narrative":"Maxwell Creek Bridge carries Hardin Road over Maxwell Creek in a rural setting of trees and fields in Napa County, California. Built in 1909, it is a single 22.5-foot span, earth-filled, closed spandrel masonry arch. The two-lane structure is 38 feet long and 19.7 feet wide, built of square-cut stone laid in regular courses, with matching stone railings. County Surveyor O.H. Buckman designed it, and contractor J.B. Newman built it for $1,875. Buckman's designs account for the many masonry arch bridges in the county, and Newman was one of the main masonry bridge contractors in the Napa valley. Nearby quarries and skilled stonemasons made stone construction practical there long after other parts of California turned to metal and concrete. The bridge was found eligible in a 1980s state bridge survey and again in a 2003 update, which noted that it keeps its original design and setting. It is listed as a rare, unaltered example of its type, and it remains in use for vehicles.","period_of_significance":"1909","architect_builder":"Buckman, O.H. (designer); Newman, J.B. (contractor)","architectural_style":"Other: Masonry Arch Bridge","criteria":["C"],"status_note":"Still in vehicular road use; the structure appears essentially unaltered, with only routine maintenance since construction.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:54:29.509599-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/05000777.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/05000777/506159d748-800.webp","url_1600":"https://nationalhistoricalregister.com/media/05000777/506159d748-1600.webp","licence":"CC BY-SA 3.0","author":"Sanfranman59","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Maxwell_Creek_Bridge_on_Hardin_Road,_Locoallomi,_CA_10-22-2011_5-25-50_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:Maxwell_Creek_Bridge_on_Hardin_Road,_Locoallomi,_CA_10-22-2011_5-25-50_PM.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123857692","wikipedia":null,"wikidata":"https://www.wikidata.org/wiki/Q113172210"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/napa-county/maxwell-creek-bridge-on-hardin-road-05000777/"}