Which province is the most westerly in Canada?

British Columbia is Canada's most westerly province, occupying the entire Pacific coast of Canada from the Alaska Panhandle to the Washington State border. The province covers 944,735 square kilometres and is home to about 5.7 million people, making it Canada's third-most populous province after Ontario and Quebec. British Columbia joined Canadian Confederation on July 20, 1871 as the country's sixth province.

The province extends from the Pacific Ocean east to the Continental Divide of the Rocky Mountains, which forms the British Columbia-Alberta border. Three major mountain systems run north-south through the province: the Coast Mountains along the Pacific shore, the Columbia Mountains in the southeast (including the Selkirks, Purcells, Monashees, and Cariboos), and the Rocky Mountains forming the eastern edge. Between these ranges lie the Interior Plateau, the Fraser Plateau, the Okanagan Valley, the Kootenay region, and the Peace River country in the northeast.

British Columbia's coastline stretches more than 25,000 kilometres including all islands, with about 40,000 islands offshore. Vancouver Island is the largest, followed by Haida Gwaii (formerly the Queen Charlotte Islands). The Inside Passage runs from Vancouver to Alaska between the mainland and offshore islands. The Port of Vancouver is the largest in Canada and the third-largest in North America by tonnage, handling about 145 million tonnes of cargo annually.

British Columbia is the most ecologically diverse Canadian province. It includes old-growth coastal temperate rainforest, dry interior grasslands, alpine and subalpine ecosystems, the Great Bear Rainforest (the largest intact temperate rainforest in the world, protected through 2016 federal-provincial-Indigenous agreements), and significant arid steppe in the Okanagan and southern Cariboo. Indigenous peoples include 198 First Nations bands and the modern Nisga'a Nation, governed under the Nisga'a Final Agreement of 2000. The British Columbia Treaty Process has produced several modern treaties since the 1990s, including the Tsawwassen Final Agreement (2009) and the Tla'amin Final Agreement (2016).