defense.gov - Domain Info
The following page provides details on the application and list of hostnames associated with the defense.gov domain. The list of notable hostnames that were detected come from not only DNS requests, but also HTTP headers, TLS certificates, DNS hinting, and other deep packet inspection methods.
You can access the full data set via the Netify Data Feed API.
The .mil domain is used by the various branches of the United States military: space force, army, navy, air force, marines and more.