Washington Revised Code Title 35. Cities and Towns § 35.02.170. Use of right-of-way line as corporate boundary--When right-of-way may be included

The right-of-way line of any public street, road or highway, or any segment thereof, may be used to define a part of a corporate boundary in an incorporation proceeding. The boundaries of a newly incorporated city or town shall not include a portion of the right-of-way of any public street, road or highway except where the boundary runs from one edge of the right-of-way to the other edge of the right-of-way.