{"nrhp_refnum":"11000214","name":"Healdsburg Memorial Bridge","other_names":["Redwood Highway Bridge, Russian River Bridge #20C-65"],"category":"structure","location":{"address":"Healdsburg Ave, junction of Front St","address_restricted":false,"city":"Healdsburg","county":"Sonoma County","state":"CA","lat":38.60394811800006,"lon":-122.86070794499994,"geom_source":"nps_gis"},"listed_date":"2011-04-14","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["local"],"summary":{"what_it_is":"A 438-foot Pennsylvania through-truss steel road bridge carrying Healdsburg Avenue over the Russian River in Healdsburg, Sonoma County, California, built in 1921 and once part of the Redwood Highway.","why_significant":"It is a rare surviving example of a Pennsylvania through-truss, a design that is fast disappearing from the American landscape, and it illustrates the evolution of steel truss bridge building. It also marks the growth of the Northern California highway system and the development of the Russian River area as a tourist destination. The Keeper's review lists significance under Criterion A and Criterion C in Engineering and Transportation.","narrative":"Spanning the Russian River at Healdsburg, this 438-foot steel bridge was completed in 1921 and once served as a landmark on the Redwood Highway linking San Francisco with Oregon. Its Pennsylvania through-truss design uses two spans with pin-connected panels and extra stress-relieving ties between the main diagonals. Only a handful of bridges of this type remain open to traffic nationwide. The structure is largely unchanged, though decorative lights were removed in the 1950s and curbs and chain-link fences were added for safety. It rests on a single concrete pier in mid-river and has survived at least five major floods. It was the first steel structure over the river. Beyond its engineering, the bridge brought tourists to local resorts and became a focus of summer events, including swimming meets and wine barrel races at a temporary dam below it. It is listed locally for its engineering and its role in transportation and regional development.","period_of_significance":"Architecture 1921; Transportation 1921-1960","architect_builder":"J.C. Lewis, architect; American Bridge Co., builder","architectural_style":"Other: Pennsylvania through-truss","criteria":["A","C"],"status_note":"Still in use as a two-lane road bridge carrying about 7,400 vehicles a day, with pedestrian and bicycle paths on the outer sides; largely unmodified 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 02:54:29.827854-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/11000214.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/11000214/8f0e13a730-800.webp","url_1600":"https://nationalhistoricalregister.com/media/11000214/8f0e13a730-1600.webp","licence":"Public domain","author":"Brian Grogan for HABS/HAER","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Healdsburg_Bridge_193708pu.jpg\" rel=\"noopener\">Brian Grogan for HABS/HAER</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Healdsburg_Bridge_193708pu.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123857820","wikipedia":"https://en.wikipedia.org/wiki/Healdsburg_Memorial_Bridge","wikidata":"https://www.wikidata.org/wiki/Q12059746"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/sonoma-county/healdsburg-memorial-bridge-11000214/"}