Montana is a state in the northern/northwestern United States, in the Rocky Mountains region. Often called Big Sky Country for its famed big, blue skies, Montana is a state of contrasts, from the flat regions to the East and the towering peaks of the Rocky Mountains in the West. Billings is the largest city in Montana and is a reference point for travelers. Visitors usually come from Yellowstone National Park to Billings to explore the western region of the U.S.