Wash. Rev. Code § 47.17.163
A state highway to be known as state route number 100 is established as follows: Beginning at a junction with state route number 101 in Ilwaco, thence westerly and southerly to Fort Canby state park; also Beginning at a junction with state route number 100 in Ilwaco, thence southerly to Fort Canby state park.
[ 1991 c 342 s 4.]
Effective dates—1991 c 342: See note following RCW 47.01.425.