The British Columbia Coast, popularly referred to as the BC Coast or simply the Coast, is a geographic region of the Canadian province of British Columbia. As the entire western continental coastline of Canada along the Pacific Ocean is in B.C., it is synonymous with being the West Coast of Canada. While the exact boundaries are variously defined, the region is generally defined to include the 15 regional districts that have coastline along the Pacific Ocean or Salish Sea, or are part of the Lower Mainland, a subregion of the British Columbia Coast. Other boundaries may exclude parts of or even entire regional districts, such as those of the aforementioned Lower Mainland. Boundaries While the term British Columbia Coast has been recorded from the earliest period of non-native settlement in British Columbia, it has never been officially defined in legal terms. The term has historically been in popular usage for over a century to describe a region of the province that extends west from the Coast Mountains and North Cascades. This definition makes the term British Columbia Coast largely synonymous with the 15 regional districts that have territory in this region. Major subregions Among locals, the British Columbia Coast can further be divided into seven major subregions: Vancouver Island: Includes Vancouver Island, the Gulf Islands, and sometimes Quadra Island. Lower Mainland: Includes Greater Vancouver, Fraser Valley, and sometimes the Sea-to-Sky Corridor. Sunshine Coast: Includes the islands and mainland coast between Howe Sound and Desolation Sound. South Coast: Includes the Lower Mainland and Sunshine Coast, but excludes Vancouver Island. This subregion is closely associated with the Salish Sea. Central Coast: Includes the islands and mainland coast between Desolation Sound and Cape Caution. This subregion is sparsely populated and is represented by the regional districts of Strathcona and Mount Waddington. The northern limit of this subregion is often extended northward to the Don Peninsula to include Central Coast Regional District. North Coast: Includes the islands and mainland coast between Cape Caution and Portland Canal. This subregion is represented by the regional districts of Central Coast, Kitimat–Stikine, and North Coast. This subregion is closely associated with the Great Bear Rainforest. Haida Gwaii: Includes the Haida Gwaii archipelago, which located about west of the mainland North Coast. History Research from the 1990s has indicated that the Ice Age-era coastline of the British Columbia Coast was lower by about . The effect of the sea