Wash. Rev. Code § 11.98B.020
(1) This chapter applies to a trust, whenever created, that has its principal place of administration in this state, subject to the following rules:
(2) Without precluding other means to establish a sufficient connection with the designated jurisdiction in a directed trust, terms of the trust which designate the principal place of administration of the trust are valid and controlling if:
[ 2020 c 303 s 3.]