The state of Montana is located in the Western United States. The western third of the state contains numerous mountain ranges; other island ranges are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name, derived from the Spanish word montaņa (mountain).
Montana has several nicknames, none official, including: "The Treasure State" and "Big Sky Country," and slogans that include "Land of the Shining Mountains," and more recently, "The Last Best Place." The state ranks fourth in area, but 44th in population, and therefore has the third lowest population density in the United States. The economy is primarily based on ranching, wheat farming, oil and coal in the east; lumber, tourism, and hard rock mining in the west. Millions of tourists annually visit Glacier National Park, the Battle of Little Bighorn site, and three of the five entrances to Yellowstone National Park. Montana is bordered by the Canadian provinces of British Columbia, Alberta and Saskatchewan on the north, Idaho on the west, Wyoming on the south and North Dakota and South Dakota on the east.
The topography of the state is diverse, and roughly defined by the Continental Divide, which runs on an approximate diagonal line through the state from northwest to south-central, splitting it into two distinct eastern and western regions. Montana is well known for its mountainous western region, most of which are geologically and geographically part of the Northern Rocky Mountains. The Absaroka and Beartooth ranges in the south are technically part of the Central Rocky Mountains. About 60% of the state is prairie, part of the northern Great Plains. Nonetheless, even east of the Continental Divide and the Rocky Mountain Front, there are a number of isolated "island ranges" that dot the prairie landscape. This island range region covers most of the central third of the state.