State, northwestern U.S. Area: 147,042 sq mi (380,837 sq km). Pop. (2009 est.): 974,989. Capital: Helena. Montana is bordered by Canada and the U.S. states of North Dakota, South Dakota, Wyoming, and Idaho. It straddles the Great Plains to the east and the Rocky Mountains to the west. Unique among the states, its rivers flow into three of the continent's primary watersheds: the Pacific, the Gulf of Mexico, and Hudson Bay. At the time of European settlement the region was inhabited by various Native American peoples, including the Cheyenne, Blackfoot, Kutenai, and Crow. Most of Montana was obtained by the U.S. through the Louisiana Purchase of 1803. The western part was disputed until 1846, when Britain relinquished its claim to the area. The Lewis and Clark Expedition (1804–06) explored Montana. St. Mary's Mission, established in 1841 by Roman Catholic missionaries, became the first permanent town as Stevensville. Gold was discovered in the early 1860s; grazing of cattle and sheep was introduced later that decade, leading to bitter battles with the Native Americans, whose hunting grounds were destroyed. Montana Territory was established in 1864. Though they defeated and killed the U.S. troops of George Armstrong Custer at the Battle of the Little Bighorn in 1876, the Native Americans ceased fighting in 1877 and were placed on reservations. Montana became the 41st state in 1889. Vast deposits of copper were found in the 1890s, and mining was the economic mainstay for almost a century. The state's economy now emphasizes tourism.