Montana (Montah'na), one of the north-western states of the American Union, bounded by the Canadian provinces of Alberta and Saskatchewan, North and South Dakota, Wyoming, and Idaho. In area - 146,080 sq. m., or nearly five times the size of Scotland - it ranks third among the states and territories, but in population only forty-fourth. The density of the population is only 1.7 person per square mile. The Rocky Mountains occupy fully one-fifth of the surface, in the south and west; the rest of the state is made up of valleys or high, rolling prairies. The head-waters of the Columbia and Missouri have their sources in Montana. The mean elevation of the state is about 3000 feet; the highest peaks of the Rocky Mountains rise to 10,000 or 12,000 feet. The Yellowstone National Park forms part of the southern boundary. In the south-east the Bad Lands extend into the state from Wyoming. The climate is mild, and the atmosphere remarkable for its clearness. The soil contains all that is needed for sustaining vegetation, but it is almost valueless without irrigation; with that, however, the yield of grains and vegetables is enormous. Stock-raising, however, is more profitable than agriculture. But the great industry is the mining and reduction of gold, silver, lead, and copper ores. The first systematic working of placer mines for gold commenced in 1862 ; in 1863 the first gold-quartz mill was built. The portion of Montana east of the Rocky Mountains was part of the Louisiana Purchase ; that to the west was part of Oregon and Washington. It was first visited by the French in 1742, and by Lewis and Clarke in 1804-6; these were followed by fur-traders and trappers, and by Jesuit missionaries. Gold was discovered in 1861. In 1864 the territory was organised, and in 1889 Montana became a state of the Union. The chief towns are the capital, Helena, and Butte City. Pop. (1870) 20,595 ; (1880) 39,159 ; (1900) 243,329.