Cultural resources reports

We strive to highlight historically significant features of Washington that demonstrate creative mitigation efforts and preserve and present the history of our transportation system.

Find videos, project webpages, information centers, and publications that demonstrate the results of creative mitigation and notable historical resources describing the history of Washington’s Transportation system, including


  • Ebey Slough Bridge (SR 529)
    • Remembering the Ebey Slough Swing Bridge – This video describes how the Ebey Slough Bridge served Snohomish County for 85 years before being replaced in 2012. Of the 16 swing bridges in 1944, only three remain today.
  • Lacey V. Murrow Memorial Bridge (I-90 Floating Bridge)
  • Manette Bridge (SR 303)
    • The Manette Bridge: Bringing People Together for 81 Years – In the 1920s, it was apparent that the communities of Manette and Bremerton needed a bridge to connect them. High costs prevented financial backing from being offered on a city, state, or federal level. Learn about how the bridge came to be built through the collaborative efforts of the city and Navy.   
  • Puyallup River/Meridian Street Bridge (SR 167)
    • The Historic Meridian Street Bridge - For more than eight decades, the Meridian Street Bridge over the Puyallup River has served as a portal for cities along the Puget Sound to the community of Puyallup. Significant for its unusual truss configuration using an unusual parabolic top cord truss design, it is the only one of its kind in Washington.
    • SR 167 Puyallup River Bridge Move – Watch a time-lapse video of the historic 1920s era steel bridge as it is lifted and moved about 60 feet to the east.
  • Simpson Avenue Bridge (US 101)
  • Tacoma Narrows Bridge
    • SR 16 Tacoma Narrows Bridge Project – The website provides information on the design, engineering, and people responsible for the fateful 1940s bridge known as “Galloping Gertie,” the 1950s replacement, and the addition in 2007 of the parallel eastbound bridge. The site includes lesson plans developed for grades 1-4 in Social Studies, Math, Science, and Language Arts for educators.



Ethnobotany is the study of the relationship between cultures and plants. As part of our aim to avoid adverse effects to historical, archaeological, and cultural resources, WSDOT promotes the protection and preservation of ethnobotanical resources.

The WSDOT Manual on Ethnobotany and Cultural Resources  is a condensed list of western Washington plants compiled by Scott Clay-Poole, PhD. The manual covers

  • Herbs
  • Shrubs/trees
  • Conifers
  • Ferns & fern-allies
  • Lichens



  • Interstate 5 (I-5)
    • The Weedin Place Nuclear Fallout Shelter was built as a prototype in 1963 to be the model for countless similar shelters that would be installed nationwide under interstate highways. The fallout shelter supports the southbound lanes of I-5 and is considered a feature of the federal interstate highway system. Learn more in the publications below:
  • SR 520
    • – Learn about 13,000 years of the landscapes, communities, and industries along the SR 520 corridor across Lake Washington. This documentation was developed as mitigation for the SR 520 Bridge replacement and HOV Project.
  • SR 99: Alaskan Way Viaduct Replacement

Washington State has several historical highways that are representative of early twentieth century highway engineering and design. These highways maintain the original alignment, road prism, and site distance providing the experience of traveling on a truly historic roadway.

Visit the pages below for detailed summaries of these historic highways

Renowned for its scenic beauty, the segment of SR 11 known as Chuckanut Drive is NRHP eligible per Criterion A for its association with early highway construction in Washington; and per Criterion C for its integrity of design, location, workmanship, feeling, and setting. Integral to the setting on the steep mountainside above Samish and Chuckanut Bays, the design of Chuckanut Drive makes it the premier historic scenic highway in the state. The segment includes three NRHP eligible bridges: Blanchard Bridge 11/7, Oyster Creek Bridge 11/8, and Padden Creek Bridge 11/102.
The 12.5 mile segment of SR 112 (formerly Neah Bay Road and Secondary State Highway 9A) extends from the Makah Indian Reservation (Mile Post 0.00) to the Hoko-Ozette Road Junction (MP 12.50). It was determined eligible for inclusion in the National Register of Historic Places under Criterion C, as it is representative of early twentieth century highway engineering, design, and construction methods in Washington State. The segment is largely intact and retains most of its character-defining features. The road also possesses many of the aspects of integrity needed for NRHP eligibility, including location, setting, and design. Perhaps most noticeable is the limited sight distance and lack of clear zones throughout the segment’s right-of-way. Those aspects preserve its integrity of feeling, giving drivers the experience of traveling on a truly historic roadway along the craggy shore of the Olympia Peninsula’s Strait of Juan de Fuca.
The 21-mile segment of SR 9 typifies a historic highway in Washington: a relatively narrow, two-lane roadway with narrow or no shoulders, with occasional widening; restricted sight distance; limited clear zones; railroad and rural road at-grade crossings; and frequent reduced speed limits due to curves, some 90 degrees. Because it has retained its overall integrity of location, feel, workmanship as seen in its dimensions and road prism, and its association with early highway development in Washington, the segment is NPRH eligible per Criteria A and C.
State Route (SR) 900, a portion of which is presently known as the Renton-Issaquah Road, was first opened to automobile traffic in 1915, as a segment of the newly created Sunset Highway. The new road passed through Snoqualmie and Blewett passes, and onto Spokane and the Idaho border. At the west end it connected with the Pacific Highway near Renton. Today, the portion of this road between the outskirts of Issaquah and the outskirts of East Renton Highlands mostly retains its two-lane appearance and 1930 alignment (and presumably the original 1915 alignment), making it the longest surviving, nearly intact segment of the original Sunset Highway. Overall, the road retains aspects of integrity justifying NRHP eligibility, including location, design, feeling, and setting.
The nearly seven-mile segment of US 101 from Mile Post (MP) 157.7 to MP 164.5 contains the last portion of the “Olympic Loop Highway” (formerly State Road 9, now US 101) built around the Olympic Peninsula. The boundaries of the segment are identified by the highway mile posts between which integrity is retained in the roadway and its prism dimensions, limited sight distance due to curves and vertical obstructions, and lack of clear zones normally present along major highways.