WAC 220-200-020
WAC 220-200-020. Definition of Eastern and Western Washington
For purposes of all rules of the commission, Eastern and Western Washington are defined as:
Eastern Washington - All lands lying east of the Cascade Crest Trail and east of the Big White Salmon River in Klickitat County.
Western Washington - All lands lying west of the Cascade Crest Trail and west of and including the Big White Salmon River in Klickitat County.