Vancouver Island, largest island on the Pacific North American Coast, off southwestern British Columbia, Canada. Vancouver is separated from mainland Canada by a series of straits. The island is the southernmost end of a partially sunken mountain range called the Vancouver Range. It has a particularly mild climate due to the flow of the Japan Current. The mountain slopes are covered with extensive cedar and fir forests. Major industries include lumber, farming, and tourism. Victoria, Vancouver Island's largest city, is the capital of British Columbia.