 As part of the U.S. Highway system laid out in 1925 and finalized in late 1926 , U.S. Route 410 connected Aberdeen with Clarkston , following the Olympic Highway ( State Road 9 ) to Olympia , the Pacific Highway ( State Road 1 ) — concurrent with US 99 — to Tacoma , the National Park Highway System ( State Road 5 ) to Yakima , and the Inland Empire Highway ( State Road 3 ) to Clarkston . This differed from present US 12 between Elma and Naches in that it followed the route through Olympia and Tacoma rather than along the Cowlitz River . However , despite being part of the state highway system since 1897 , US 410 's crossing of the Cascades , the first between the Columbia River Gorge and Snoqualmie Pass , was not opened to traffic until 1931 . A shortcut from near Packwood east across White Pass to Naches , very close to the original plan for the east half of State Road 5 , was added to the state highway system in 1931 as another branch of the highway . The roadway between Packwood and Cayuse Pass , added to the state highway system on a different alignment in 1905 , was finally completed in 1940 , and the White Pass Highway was dedicated on August 12 , 1951 , opening a shortcut between southwest Washington and Yakima . 
