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.

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.

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.