Arizona's Yuma Proving Ground
- The proving ground conducts tests on nearly every weapon system in the ground combat arsenal. Munitions and artillery systems are tested here in an area almost completely removed from urban encroachment and noise concerns. Restricted airspace controlled by the test center amounts to over 2,000 square miles (5,000 km2). Nearly 3000 people, mostly civilian, work at the proving ground. It is a major economic player in Yuma County, with an economic impact of over $430 million annually. Yuma Proving Ground is the largest single employer of civilians in the county.