The United States descended into civil war as a result of internal disagreements between the states. General Lamson won that war and instituted the American Union soon afterward. The new American Union spanned all of North America, including Canada and Mexico. To preserve the peace, General Lamson also introduced Cylis's Mark program as a part of the Unity.
As a result of environmental disasters, the bulk of the A.U.'s population is centered in three major metropolitan areas.
Beacon City is the largest of the American Union's metropolitan areas, as well as the economic center of both the American and European Unions. It extends from the eastern seaboard to the Allegheny River.
New Chicago is smaller geographically than Beacon, but it is densely populated. This oval-shaped metropolitan area extends across the Great Lakes and into Canada.
Hot and vibrant, Sierra City is growing from the American Southwest into Mexico. It is the newest of the three epicenters of the A.U., since much of the old West Coast was destroyed in an earthquake. Sierra City tends to approach the concept of law from a very relaxed point of view; the library is filled with banned books.
The American Union is ruled by a Parliament, to which representatives are elected by the vote of the Marked population.
The economy of the American Union is centered in Beacon City. Most major economic activity takes place on Barrier Street.