The westernmost of Canada's provinces. British Columbia is bordered by the Pacific Ocean on the west, by the American State of Alaska on the northwest, and to the north by the Yukon and the Northwest Territories, on the east by the province of Alberta, and on the south by the States of Washington, Idaho, and Montana. The current southern border of British Columbia was established by the 1846 Oregon Treaty, although its history is tied with lands as far south as the California border. British Columbia's rugged coastline stretches for more than 27,000 km, and includes deep, mountainous fjords and about 6,000 islands, most of which are uninhabited. British Columbia is carved into 27 regional districts. These regional districts are federations of member municipalities and electoral areas. The unincorporated area of the regional district is carved into electoral areas.