The Northwestern United States is an informal geographic region of the United States. The region consistently includes the states of Oregon, Washington, and Idaho — and usually Montana and Wyoming. Some sources include southeast Alaska in the Northwest. The related but distinct term "Pacific Northwest" generally excludes areas from the Rockies eastward. It is home to over 13 million citizens. Some of the fastest growing cities in this region and in the nation include Seattle, Bellevue, Tacoma, Vancouver, Kennewick, Pasco, Yakima, and Boise.