What Part Of The United States Is More Mountainous, Eastern Or Western?

In both height and acreage, the west takes the trophy, because the Pacific Plate is still pushing under and raising up the North American Plate, which so far has produce the following mountain range:  The Rockies, the Cascades, the Olympics, the Sierra, and the Coast Range.   Here's a good map that shows the mountainous areas in brown:  www.united-states-map.com  For the world's tectonic plates, see en.wikipedia.org