a large state in the north-western US, on the Canadian border. The capital city is Helena, and the largest city is Billings. Montana became a state in 1889, and is also called the Treasure State. It produces many minerals, and its mines once supplied half of all US copper (= a soft reddish-brown metal). It also produces grain, potatoes, sheep and cattle. Montana's tourist attractions include the Rocky Mountains, Yellowstone National Park, the Glacier National Park and the Little Bighorn Battlefield National Monument.