Washington Revised Code Title 11. Probate and Trust Law § 11.96A.040. Original jurisdiction in probate and trust matters--Powers of court

(1) The superior court of every county has original subject matter jurisdiction over the probate of wills and the administration of estates of incapacitated, missing, and deceased individuals in all instances, including without limitation:

(2) The superior court of every county has original subject matter jurisdiction over trusts and all matters relating to trusts.

(3) The superior courts may: Probate or refuse to probate wills, appoint personal representatives, administer and settle the affairs and the estates of incapacitated, missing, or deceased individuals including but not limited to decedents' nonprobate assets; administer and settle matters that relate to nonprobate assets and arise under chapter 11.18 or 11.42 RCW; administer and settle all matters relating to trusts; administer and settle matters that relate to powers of attorney; award processes and cause to come before them all persons whom the courts deem it necessary to examine; order and cause to be issued all such writs and any other orders as are proper or necessary; and do all other things proper or incident to the exercise of jurisdiction under this section.

(4) The subject matter jurisdiction of the superior court applies without regard to venue. A proceeding or action by or before a superior court is not defective or invalid because of the selected venue if the court has jurisdiction of the subject matter of the action.