Approximately 31,300,000 acres (127,000 km) of wilderness in 12 separate wilderness areas that are part of the National Wilderness Preservation System established by the Wilderness Act of 1964. Montana is a large state with considerable variation in geography, topography and altitude, and the climate is, therefore, equally varied.
The state spans from below the 45th parallel (the line equidistant between the equator and North Pole) to the 49th parallel, and elevations range from under 2,000 feet (610 m) to nearly 13,000 feet (4,000 m) above sea level.
Montana contains Glacier National Park, "The Crown of the Continent"; and portions of Yellowstone National Park, including three of the park's five entrances. Department of the Interior Bureau of Reclamation administers approximately 300,000 acres (1,200 km) of School Trust Land ceded by the federal government under the Land Ordinance of 1785 to the state in 1889 when Montana was granted statehood.
Other federally recognized sites include the Little Bighorn National Monument, Bighorn Canyon National Recreation Area, Big Hole National Battlefield, and the National Bison Range. Department of the Interior Bureau of Land Management controls 8,100,000 acres (33,000 km) of 1.1 million acres of National Wildlife Refuges and waterfowl production areas in Montana. These lands are managed by the state for the benefit of public schools and institutions in the state.
Montana is one of few geographic areas in the world whose rivers form parts of three major watersheds (i.e. Its rivers feed the Pacific Ocean, the Gulf of Mexico, and Hudson Bay.
The area west of the divide has a modified northern Pacific coast climate, with milder winters, cooler summers, less wind and a longer growing season.
The western half is mountainous, interrupted by numerous large valleys.
Eastern Montana comprises plains and badlands, broken by hills and isolated mountain ranges, and has a semi-arid, continental climate (Köppen climate classification BSk).
Other major reservoirs include Hungry Horse on the Flathead River; Lake Koocanusa on the Kootenai River; Lake Elwell on the Marias River; Clark Canyon on the Beaverhead River; Yellowtail on the Bighorn River, Canyon Ferry, Hauser, Holter, Rainbow; and Black Eagle on the Missouri River.
See also: List of monocotyledons of Montana, List of coniferous plants of Montana, List of lichens of Montana, List of amphibians and reptiles of Montana, List of birds of Montana, Fish of Montana, Mammals of Montana, and List of taxa described from Montana Vegetation of the state includes lodgepole pine, ponderosa pine; Douglas fir, larch, spruce; aspen, birch, red cedar, hemlock, ash, alder; rocky mountain maple and cottonwood trees.