NIPRNet

From GovITwiki

Now known as the Unclassified but Sensitive Internet Protocol Router Network, the NIPRnet name actually comes from this network's former moniker, the Non-Classified Internet Protocol Router Network.

This system is used to exchange unclassified but sensitive information between internal users. It also provides participants with access to the Internet.

Owned and managed by the Department of Defense NIPRnet was created by the Defense Information Systems Agency (DISA). It essentially supersedes the earlier network known as MILNET, one of the most important networks on the early Internet.

The GovITwiki Intelligence Agencies page lists the U.S. government's major secret and sensative but Unclassified networks.