Island county shall consist of all of the islands known as Whidbey, Camano, Smith, Deception, Strawberry, Baby, Minor, Kalamut, and Ben Ure and shall extend into the adjacent channels to connect with the boundaries of adjoining counties as defined by statute.
During the Vashon Glaciation, the Cordilleran Ice Sheet grew and advanced southwards at a rate of about 135 metres (443 ft) per year.