TheRegional designations of Montana vary widely within theU.S state ofMontana. The state is a large geographical area (147,046 square miles (380,850 km2)) that is split by theContinental Divide, resulting inwatersheds draining into thePacific Ocean,Gulf of Mexico andHudson's Bay. The state is approximately 545 miles (877 km) east to west along theCanada–United States border and 320 miles (510 km) north to south. The fourth largest state in land area, it has been divided up in official and unofficial ways into a variety of regions. Additionally, Montana is part of a number of larger federal government administrative regions.
Medicine Line, the name given the 49th parallel border between the U.S. and Canada betweenLake of the Woods and the continental divide byNative Americans because of its seemingly magical ability to prevent U.S. soldiers from crossing it.[3]
Montana east of the continental divide and Wyoming make up the Rocky Mountain Region of theBureau of Indian Affairs (BIA) which includes the following Indian agencies in Montana.[20]
TheBureau of Land Management (BLM) includes Montana with North and South Dakota in its Montana-Dakotas region.The BLM administers Montana through nine regional field offices.[27]
The NWS designates regional weather reports originating from these offices as Southeastern Montana, Northeastern Montana, Central Montana and Western Montana/Central Idaho.[29]
In theKöppen climate classification system, Montana is predominantly aBSk (Semi-arid or Steppe) climate, with the Mountainous areas, mostly in the western parts of the state, listed as Dfb (humid continental). Areas nearGranite Peak and the highest elevations in Glacier National Park areDfc (Continental subarctic), and a small area in the northwestern corner of the state near the Idaho border listed asDsb (Warm summer continental).[32] TheUnited States Department of Agriculture places most of Montana inPlant Hardiness Zones 3 and 4, with limited areas in zone 5 with a small sliver of the state centered in Sanders County in zone 6. These zone boundaries correspond closely to the Köppen classifications.[33] For purposes of the 2009International Energy Conservation Code, which provides minimum insulation standards for home construction based on climate, the entire state is classified in climate zone 6, requiring higher levels of insulation than are recommended in more temperate climates.[34]
^Vichorek, Daniel N. (1993).The Hi-Line, Profiles of a Montana Land. Helena, Montana: American World and Geographic Publishing. p. 7.ISBN1-56037-021-1.
^Rees, Tony (2007).Arc of the Medicine Line-Mapping the World's Longest Undefended Border Across the Western Plains. Lincoln, NE: University of Nebraska Press. p. 5.ISBN978-0-8032-1791-1.
