Wash. Rev. Code § 47.17.155
A state highway to be known as state route number 97 is established as follows:
Beginning at the Washington-Oregon boundary on the interstate bridge across the Columbia river at Biggs Rapids, thence in a northerly direction to the junction with state route number 14 in the vicinity of Maryhill, thence in a northerly direction by way of Goldendale, thence northeasterly by way of Satus Pass to a junction with state route number 22 at Toppenish, thence northwesterly south of the Yakima river to a junction with state route number 82 at Union Gap; also
Beginning at a junction with state route number 90 in the vicinity of Ellensburg, thence northeasterly by way of Swauk Pass to a junction with state route number 2 in the vicinity of Peshastin; also
Beginning at a junction with state route number 2 in the vicinity north of Orondo, thence northerly by way of the vicinities of Chelan, Pateros, Brewster, Okanogan, and Oroville to the international boundary line.
RCW 47.17.155