British Columbia is bordered by the Pacific Ocean on its west, by the American state of Alaska on its Northwest, and to the north by the Yukon Territory 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 up with lands as far south as the Columbia River.

British Columbia's land area is 944,735 square kilometers (364,764 square miles) which is about the size of France, Germany and the Netherlands combined. It is larger than the total area of Washington, Oregon and California. British Columbia's rugged coastline stretches for more than 27,000 kilometers (16,780 miles), including deep, mountainous fjords and about 6,000 islands, most of which are uninhabited.