[3] Following the completion of the North Cascades Highway in 1972, SR 20 was extended east to form a cross-state route under a single number.

[4][5] US 95, a major north–south route between Arizona and the Canadian border, ran for 0.91 miles (1.46 km)[1]: 75  in Whitman County, Washington, from 1926 to 1979.

[8] State Route 110 was established in 1967 as SSH 1F, a short connector between Chuckanut Drive (SR 11) and I-5 (formerly PSH 1) that had been planned to be built.

[17][18] SR 11 was routed onto the new highway upon its completion as part of a provision added by the state legislature in 1971.

[citation needed] A paved highway to Hurricane Ridge was completed by the National Park Service in 1957 as part of their Mission 66 program.

It was a steep and unpaved route that connected two sections of US 12 with the foothills of the Blue Mountains in Columbia and Garfield counties.

[citation needed] State Route 131 was a 16-mile (26 km) highway[1]: 106  that connected two sections of US 97 between Ellensburg and Virden in Kittitas County.

[23] The highway was rebuilt in 1975 and incorporated into US 97, as it provided a shorter route between Ellensburg and Blewett Pass.

[5][26] The tolls were removed on August 30, 1974, and ownership was transferred on November 1, with Washington assuming maintenance duties.

It started at SR 207 in Lake Wenatchee State Park and went east to the community of Plain and then south to U.S. Route 2 near Leavenworth.

[citation needed] State Route 276 was a proposed northern bypass of Pullman between US 195 and SR 270 that was never built.

It traveled east on Sylvan Way for 1.5 miles (2.4 km) from SR 303 to the state park entrance.

[40] The highway was originally assigned the designation of SR 831 during the 1964 renumbering to replace a short branch of PSH 12 that had been created a year earlier.

[43] Control of the highway was transferred to local governments in 1992 as part of a swap that included an extension of SR 432.

The majority of the highway was transferred to county control in 1992, with the exception of the east–west section between Winlock and I-5 that was renumbered to part of SR 505.

At the time of its creation, SR 901 began at the intersection of Lake Washington Boulevard and State Route 520, on the border of Kirkland and Bellevue.

It then followed West Lake Sammamish Parkway into Issaquah, ending at its intersection with State Route 900.

[citation needed] Effective April 1, 1992, SR 901's path was changed again; now it ran through the city of Sammamish along East Lake Sammamish Parkway from Front Street in Issaquah to State Route 202 east of downtown Redmond.

In June, SR 901 was completely dropped as a state route in Washington, following outcry from residents on East Lake Sammamish Parkway.