What is the setting of Die Trying by Lee Child?

The novel begins in Chicago where Holly lives and works. Holly and Reacher are snatched off the street and forced into a car. Soon they are forced into another vehicle where they remain as the vehicle is driven more than a thousand miles to their eventual destination. The novel then travels to Washington DC, where the director of the FBI informs Holly's father, the Chairman of the Joint Chiefs of Staff, of her abduction. Finally, the novel moves to Montana, where Beau Borken has created a new nation in a far corner of Montana.