October 4, 2013, 12pm PDT
What if the great adventurer and geographer John Wesley Powell had his way: That as the western states were brought into the union their shape would be dictated by watershed rather than political boundary? This blog - and map - depict this scenario.
November 21, 2010, 11am PST
This post from GOOD points to an old map of the Western U.S. in which state lines are redrawn based on the locations of watersheds.