Northern Commonwealth

The  was one of the thirteen commonwealths of the pre-war United States of America. Created in the early 21st century, it was comprised of the former states of Montana, Wyoming, North Dakota and South Dakota.

Wyoming Wasteland
In 2281, the Great Khans could have abandoned the Mojave, and created a great empire in the state of Wyoming, raining terrible dark-age in the area for years to come. Also, the White Legs can flee to Wyoming after their leader, Salt-Upon-Wounds, is killed.

Montana Wasteland
Nothing much is known about this area, except that the Courier stopped through at some point.

Appearances
The Northern Commonwealth does not appear in any released Fallout games. One of its states, Wyoming, is mentioned in one of the Fallout: New Vegas endings regarding the Great Khans. Montana was also a place the Courier explored.