Do you want good names for all those?Face it, except for New England, all American regional names suck. The Midwest (Subdivided into the Great Plains and the Great Lakes), the South (subdivided into the Upper South and the Deep South), the Pacific Northwest, the Mountainous West, the Desert Southwest and the Midatlantic. None are really "good" names.
Midwest: Just split it in GP and GL.
South: Southland or Dixie.
Pacific Northwest: Cascadia
Mountainous West: Rockia or Rockyland
Desert Southwest: El Norte or North Mexico
Midatlantic: Heartland.