Wash. Rev. Code § 47.17.300
A state highway to be known as state route number 155 is established as follows: Beginning at a junction with state route number 2 in the vicinity north of Coulee City, thence northeasterly to the boundary of the federal reservation at the Grand Coulee dam; also Beginning at the boundary of the federal reservation at the Grand Coulee dam, thence northwesterly by the most feasible route by way of Nespelem and Disautel to a junction with state route number 97 at Omak; also Beginning at a junction with state route number 155 at Omak, thence northwesterly crossing the Okanogan river to a junction with state route number 215 at Omak.
[ 1975 c 63 s 4; 1970 ex.s. c 51 s 61.]