Portions of the United States is often referred to by region.
Which States are in the Southwest U.S.?
There is no official designation of states by region, so when you hear or read about the Southwest U.S. it might be unclear exactly which states are included. The states referred to as being in the Southwest may or may not be California, Nevada, Utah, Colorado, Oklahoma, Texas, or parts of those states. It just depends on the topic. A discussion about weather or ecology might include some states, while a discussion about Native American or Mexican history and culture in that region might include other states.
In Which Region Does Arizona Belong?
Notwithstanding what I just wrote, there seems to be general agreement that both Arizona and New Mexico are always
considered to be in the Southwest.
Part 1: Which States Are in the Southwest?
Part 2: Where is Arizona?
Part 3: Where is Maricopa County?
Part 4: Where is Phoenix?