Washington Revised Code Title 36. Counties § 36.05.030. Residents of area may intervene

A majority of the voters living in the territory embracing such disputed, lost, obscure, or uncertain boundary line may, by petition, duly verified by one or more of them, intervene in the suit, and thereupon the court shall have jurisdiction and power, in locating and establishing the boundary line or lines, to strike or transfer from one county to another a strip or portion of such territory not exceeding two miles in width.