Air Force Space Surveillance System
Just north of Maricopa is the Air Force Space Surveillance System or "Space Fence". It is a large antenna which beams hi-power radar waves into space. It is one of many radar stations used to detect space junk for NASA and the Air Force. In 2013 it was shut down in response to "federal sequestration cuts".
Michael and I found it still intact but abandoned.
You can still see it on Google Maps for the time being.