{"nrhp_refnum":"08000316","name":"Washburn Tunnel","other_names":[],"category":"structure","location":{"address":"3100 Federal Rd.","address_restricted":false,"city":"Houston","county":"Harris County","state":"TX","lat":29.71913179300003,"lon":-95.21189675699998,"geom_source":"nps_gis"},"listed_date":"2008-04-16","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"A two-lane subaqueous vehicular tunnel under the Houston Ship Channel of Buffalo Bayou, connecting Galena Park and Pasadena in Harris County, Texas. Designed in 1947 and opened in May 1950, it includes a 3-story control building, a roundabout and a traffic circle.","why_significant":"The nomination presents it as the first underwater traffic artery in Texas and the second toll-free tunnel in the United States. It replaced a 1916 ferry and reflects the industrialization of the ship channel and suburban growth in Pasadena and Galena Park. It is recognized under Criterion C for engineering and transportation.","narrative":"Running beneath the Houston Ship Channel, this 3,791-foot vehicular tunnel links Galena Park on the north with Pasadena on the south. Designed in 1947 by Palmer & Baker and built by Merritt-Chapman & Scott, it opened in May 1950. Two welded steel tubes, one inside the other, are filled between with concrete and wrapped in a further two feet of concrete. The interior is lined with more than a million glazed ceramic tiles. A three-story control building over the north entrance houses ventilation and security systems. Harris County planned the crossing to replace a ferry in service since 1916, which conflicted with heavy ship and barge traffic. It was the first underwater traffic artery in Texas and the second toll-free tunnel in the United States. Renovations between 1987 and 1991 replaced the roadbed and systems and added zinc siding over the original control building facades. The tunnel remains in use and retains a high degree of integrity.","period_of_significance":"1947-1958","architect_builder":"Designers: Palmer and Baker, Consulting Engineers, Mobile, Alabama; Engineers and Contractors: Merritt-Chapman and Scott Corporation of New York","architectural_style":"Other: Subaqueous tunnel","criteria":["C"],"status_note":"In continuous operation as a vehicular tunnel since opening in May 1950; renovated 1987-1991, with the control building covered in zinc siding.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:54:24.180311-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/78/9724/40972478/content/electronic-records/rg-079/NPS_TX/08000316.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/08000316/6f25e7fbf9-800.webp","url_1600":"https://nationalhistoricalregister.com/media/08000316/6f25e7fbf9-1600.webp","licence":"CC BY 2.0","author":"Accent on Electric","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Washburn_Tunnel_Harris_Co_TX.jpg\" rel=\"noopener\">Accent on Electric</a>, <a href=\"https://creativecommons.org/licenses/by/2.0\" rel=\"license noopener\">CC BY 2.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Washburn_Tunnel_Harris_Co_TX.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/40972478","wikipedia":"https://en.wikipedia.org/wiki/Washburn_Tunnel","wikidata":"https://www.wikidata.org/wiki/Q7971462"},"indexable":true,"url":"https://nationalhistoricalregister.com/texas/harris-county/washburn-tunnel-08000316/"}