Montana is a U.S. state in the Pacific Northwest and Great Plains regions of the United States. The central and western thirds of the state have numerous mountain ranges (approximately 77 named) of the northern Rocky Mountains. The state ranks fourth in size but has a relatively low population (with only six states having fewer people) and consequently a very low population density. The economy is primarily based on agriculture and significant lumber and mineral extraction. Tourism is also important to the economy, with millions of visitors a year to Glacier National Park, the Battle of Little Bighorn site, and three of the five entrances to Yellowstone National Park...