Western things

When looking for maps that document great change and development in the U.S., many think that things from the 20th century are far too recent. Indeed, east of the Mississippi River, by the late 19th century, not much will be radically altered save for additions of suburbs and highways. 

But in the West, continued waves of settlement in the 20th century will spawn new towns, counties and even change long standing "Territories" into legitimate "States".

Here, a ridiculously biased list of some maps related to the U.S. West many from the early 20th century, with the preponderance of them focused on things Colorado.