State of the U.S., lying at the northwestern extremity of North America. Area: 589,194 sq mi (1,526,005 sq km). Pop. (2009 est.): 698,473. Capital: Juneau. Alaska is largest in area of the U.S. states. It is bordered by Canada to the east and southeast and faces Siberia across the Bering Strait and Bering Sea to the west, and it has the highest point on the continent, Mount McKinley. The original inhabitants are thought to have migrated over the Bering Land Bridge as well as from the Arctic as early as 10,000 BCE. The first European settlement was established in 1784 by Russian fur traders on Kodiak Island. Hudson's Bay Co. traders were also interested in the same area, and Russian-Canadian trade rivalry lasted well into the 19th century. In 1867 William Seward negotiated Alaska's sale from the Russians to the U.S., and the subsequent discovery of gold stimulated American settlement. Alaska was a U.S. territory from 1912 until it was admitted as the 49th state in 1959. Its economy has become increasingly centred on services (research and tourism), but since the opening of the Trans-Alaska Pipeline in 1977, Alaska has accounted for about one-fifth of all the oil produced in the United States. Since the mid-20th century, the question of development versus preservation has been heightened by the often competing agendas of commercial interests and environmentalists. Moreover, global warming has greatly affected Alaska's climate, causing permafrost to thaw and sea ice to melt.