{"nrhp_refnum":"87000566","name":"Fernbridge","other_names":["Eel River Bridge"],"category":"structure","location":{"address":"CA 211","address_restricted":false,"city":"Fernbridge","county":"Humboldt County","state":"CA","lat":40.614103183000054,"lon":-124.20327309099997,"geom_source":"nps_gis"},"listed_date":"1987-04-02","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["state"],"summary":{"what_it_is":"Fernbridge is a seven-span reinforced concrete earth-filled spandrel arch bridge carrying State Route 211 across the Eel River at Fernbridge, Humboldt County, California, built in 1911 with concrete approaches added in 1920.","why_significant":"The nomination argues it was an outstanding engineering feat when built in 1911, and its 196-foot spans remain the longest of their type in California. It has survived major floods in 1955 and 1964 and retains a high degree of historic integrity. It was named a California Historic Civil Engineering Landmark in 1976 and ranked first among earth-filled spandrel arch bridges in a 1986 state survey.","narrative":"Spanning the Eel River on State Route 211, Fernbridge is a reinforced concrete arch bridge more than 2,400 feet long, linking the Eel River valley and Ferndale with Highway 101. Completed in November 1911 after years of petitions by valley residents who were cut off by winter floods, it has seven earth-filled spandrel arch spans of 196 feet each, the longest of that design in California. Designed under County Surveyor George Conners and attributed to engineer John B. Leonard, it was built by the Pacific Construction Company on timber-pile foundations. Wooden approaches were replaced with concrete ones in 1920. The bridge withstood the major floods of 1955 and 1964, though the south end was shortened by 20 feet after the first. It was recognized as a civil engineering landmark in 1976 and is valued for its engineering, durability and appearance, and for its role in the valley's dairy economy.","period_of_significance":null,"architect_builder":"1911: George W. Conners, County Surveyor; John B. Leonard, Consulting Engineer; Pacific Construction Company. 1920: A.J. Logan, County Surveyor; H.J. Brunnier, Consulting Engineer; Padgett and Kelly, Contractor","architectural_style":null,"criteria":[],"status_note":"Described as in good condition, occupied and in use as a public transportation structure, with the state considering its condition and alternatives at the time of nomination.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:54:27.993206-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/87000566.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/87000566/62401693ec-800.webp","url_1600":"https://nationalhistoricalregister.com/media/87000566/62401693ec-1600.webp","licence":"Public domain","author":"Originally uploaded by Monotropa uniflora","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Fernbridge.JPG\" rel=\"noopener\">Originally uploaded by Monotropa uniflora</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Fernbridge.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123858746","wikipedia":"https://en.wikipedia.org/wiki/Fernbridge_(bridge)","wikidata":"https://www.wikidata.org/wiki/Q5445038"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/humboldt-county/fernbridge-87000566/"}