 Its northern boundary follows the shoreline of Vancouver Island from Carmanah Point to Gonzales Point, then follows a continuous line east to Seabird Point (Discovery Island), British Columbia, Cattle Point (San Juan Island), Washington, Iceberg Point (Lopez Island), Point Colville (Lopez Island), and then to Rosario Head (Fidalgo Island).The eastern boundary runs south from Rosario Head across Deception Pass to Whidbey Island, then along the western coast of Whidbey Island to Point Partridge, then across Admiralty Inlet to Point Wilson (Quimper Peninsula).The northern coast of the Olympic Peninsula forms the southern boundary of the strait.