Indiana Code Title 13. Environment § 13-11-2-129.6

(1) has an area of at least sixty thousand (60,000) acres and is used for the design, construction, maintenance, and testing of electronic devices and ordnance;

(2) has an area of at least nine hundred (900) acres and serves as an urban training center for military units, civilian personnel, and first responders;  or

(3) has an area of at least five thousand (5,000) acres and serves as a joint training center for active and reserve components of the armed forces of the United States.