Wash. Rev. Code § 47.17.295
A state highway to be known as state route number 153 is established as follows: Beginning at a junction with state route number 97 in the vicinity of Pateros, thence northerly and westerly by the most feasible route to a junction with state route number 20 in the vicinity south of Twisp.
[ 1970 ex.s. c 51 s 60.]