The ACUB program supports the Army's mission to fight and win the nation's wars. Winning wars requires a trained and ready force. Trained and ready Soldiers require land for maneuver exercises, live fire training, equipment and Soldier skill testing, and other operations. Training restrictions, costly workarounds, and compromised training realism can result from incompatible development surrounding the installation (external encroachment) and from threatened and endangered species on the installation (internal encroachment). Title 10, Section 2684a of the United States Code authorizes the Department of Defense to form agreements with non-federal governments or private organizations to limit encroachments and other constraints on military training, testing, and operations by establishing buffers around installations. The Army implements this authority through the ACUB program, which is managed overall at Army Headquarters level by the office of the Assistant Chief of Staff for Installation Management (OACSIM). Active Army cooperative agreements are managed by USAEC (a subcommand of Headquarters Installation Management Command [IMCOM]) and Army National Guard Directorate ACUB cooperative agreements are managed by the Army National Guard Environmental Programs Division.

The ACUB program allows installations to work with partners to encumber off-post land to protect habitat and buffer training without acquiring any new land for Army ownership. Through ACUB, the Army reaches out to partners to identify mutual objectives of land conservation and to prevent development of critical open areas. The Army can contribute funds to the partner’s purchase of easements or properties from willing landowners. These partnerships preserve high-value habitat and limit incompatible development in the vicinity of military installations. Establishing buffer areas around Army installations limits the effects of encroachment and maximizes land inside the installation that can be used to support the installation's mission.