{"nrhp_refnum":"05000776","name":"Garnett Creek Bridge on CA 29","other_names":["Bridge No. 21-0005"],"category":"structure","location":{"address":"CA 29 over Garnett Creek at postmile 39.08","address_restricted":false,"city":"Calistoga","county":"Napa County","state":"CA","lat":38.59303861300003,"lon":-122.59139350199996,"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 three-span, earth-filled, closed spandrel masonry arch bridge carrying State Highway 29 over Garnett Creek near Calistoga, Napa County, California. The first span was built in 1902 and two more were added in 1914.","why_significant":"The bridge is argued to be a good example of the many masonry arch bridges built in Napa County in the late nineteenth and early twentieth centuries, and a fine example of a rare bridge type in California. It is the only masonry arch bridge on a state highway in Napa County that retains sufficient integrity to be considered eligible. It was listed under Criterion C in the area of engineering at the local level.","narrative":"Carrying State Highway 29 over Garnett Creek near Calistoga, this stone arch bridge was built in two phases twelve years apart. The first span went up in 1902, designed by J.M. Graham and built by contractor H.W. Wing. In 1914 two more spans were added on the southeast side, designed by Napa County Surveyor O.H. Buckman and built by A.C. Martini for $2,759. The result is an 81-foot, two-lane structure with a 19.5-foot roadway, made of square-cut stone laid in irregular courses, with stone railings. Its outer spans measure 20 feet and the middle span 25 feet. It was listed for its engineering significance as an example of masonry arch construction, a rare bridge type in California. Napa County kept building stone bridges long after other regions abandoned them, helped by nearby quarries and skilled stonemasons. Surveys in the 1980s and in 2003 found that the bridge retains its design and setting, and it is the only masonry arch bridge on a state highway in the county judged eligible.","period_of_significance":"1902, 1914","architect_builder":"Graham, J.M. (designer); Wing, H.W. (contractor)","architectural_style":"Other: Masonry Arch Bridge","criteria":["C"],"status_note":"Still in vehicular road use as a state highway bridge, in a rural setting of trees and fields.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:54:29.628398-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/05000776.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/05000776/a52c83a570-800.webp","url_1600":"https://nationalhistoricalregister.com/media/05000776/a52c83a570-1600.webp","licence":"CC BY-SA 3.0","author":"Sanfranman59","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Garnett_Creek_Bridge_on_CA_29,_postmile_39.08,_Calistoga,_CA_10-22-2011_3-50-20_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:Garnett_Creek_Bridge_on_CA_29,_postmile_39.08,_Calistoga,_CA_10-22-2011_3-50-20_PM.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123857688","wikipedia":null,"wikidata":"https://www.wikidata.org/wiki/Q133307927"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/napa-county/garnett-creek-bridge-on-ca-29-05000776/"}