Montana is a state in the northern Great Plains of the United States. It was admitted to the Union in 1889 as the 41st state. It is bordered by North and South Dakota to the east, Wyoming to the south and southeast, Idaho to the west and southwest, and the three Canadian provinces of British Columbia, Alberta, and Saskatchewan to the north. Helena is the capital.
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 montaña (mountain). The state ranks fourth in area, but 44th in population, and therefore has the third lowest population density in the United States.
Paula Shaffer time traveled to Montana during the Upper Cretaceous Period to do a field study of hadrosaurs.
Montana was one of the sparsely populated parts of the United States that President Joe Steele exiled dissidents to. Mike Sullivan ended up in an encampment in Montana.
 Montana territory was the site of United States' defeat the British and Canadians at the Battle of the Teton River, the country's only substantive victory during the Second Mexican War. George Armstrong Custer and Theodore Roosevelt commanded the American forces that defeated a British invasion from Canada and both went on the become important military and political leaders, as well as bitter rivals.
After this event, Montana was never again invaded by enemy forces, even though the United States fought Canada again during the
Politically, Montana was firmly a
Democratic stronghold. For example, the state voted for  Calvin Coolidge in the 1928 presidential election, though he lost to Socialist Vice President Hosea Blackford by a narrow margin.
Montana was directly impacted by the eruption of the Yellowstone Supervolcano, with several towns next to Yellowstone National Park wiped off the map altogether. The  President declared a state of emergency in Montana and the governor called out the National Guard. The western part of the state did manage to sustain itself for a time, if barely. 
In the initial aftermath of the eruption,
Kelly Birnbaum was able to find shelter in Missoula, Montana, which was just outside of the blast-zone.
The western portion of
Montana remained part of the United States after the Krolp invasion. The renegade Krolp who killed President Harris Moffatt II fled to West Yellowstone, Montana, where he was finally killed by American forces.
Montana's location within the United States kept it isolated from the Race's invasion in 1942. The staff of the University of Chicago's Metallurgical Laboratory passed through Montana on their way to Denver.
Albertus, Hanover (province), Oregon (The Two Georges), Washington (province)
OTL Montana is split among four provinces of the North American Union:
Albertus: Controls central western portion along with all of OTL Alberta.
Hanover: Controls the southeastern portion along with all of OTL Wyoming, southwestern South Dakota, eastern Colorado, and Nebraska north of the Platte River.
Oregon: Controls the northwestern portion along with all of OTL Oregon and Washington, most of Idaho, and a small chunk of northwestern Nevada.
Washington: Controls the northeastern portion along with all of Saskatchewan, western North Dakota, and northwestern South Dakota.
, pg. 174, HC. Joe Steele
, pgs. 480-491. How Few Remain
, pg. 218. The Center Cannot Hold
, see, e.g. pg. 159. Eruption
↑ Ibid., pg. 162.
↑ Ibid., pg. 223.
↑ Ibid., pgs. 205-227, generally.
, pg. 154-155. Tilting the Balance ↑ Map
, frontispiece. The Two Georges