The generic top-level domain for the United States Department of Defense and its subsidiary organizations.
It was one of the first top-level domains, created in January 1985.
The United States is the only country that has a top-level domain for its military.
Other countries often use second-level domains for this purpose, e.g., .mod.uk for the United Kingdom’s Ministry of Defence.
Although the United States military has its own top-level domain, it still uses .com domains for some of its recruitment sites, such as goarmy.com.
Internet purists consider this to be improper, as it is not a commercial entity.
Also, the military uses .edu domains for its service academies: the United States Military Academy, United States Naval Academy, and the United States Air Force Academy can all be reached using either an .edu or a .mil domain.
The official athletic program sites of all three academies use .com domains.
The Department of Defense is, however, also using some “vanity domains” within .mil in recent times, such as americasupportsyou.mil.