Unified Combatant Command

A Unified Combatant Command (UCC) is a United States Department of Defense command that is composed of forces from at least two Military Departments and has a broad and continuing mission. These commands are established to provide effective command and control of U.S. military forces, regardless of branch of service, in peace and war. They are organized either on a geographical basis (known as "Area of Responsibility", AOR) or on a functional basis. UCCs are "joint" commands with specific badges denoting their affiliation.

The Unified Command Plan (UCP) is updated annually in conjunction with the DoD Fiscal Year and can modify areas of responsibility or combatant command alignments or assignments. As of September 2011, there are nine Unified Combatant Commands as specified in Title 10 and the latest annual UCP. Six have regional responsibilities, and three have functional responsibilities.

Each unified command is led by a Combatant Commander (CCDR), who is a four-star general or admiral. CCDRs exercise combatant command (COCOM), a specific type of nontransferable command authority over assigned forces, regardless of branch of service, that is vested only in the CCDRs by federal law in 10 U.S.C. § 164. The Chain of Command for operational purposes (as per the Goldwater–Nichols Act) goes from the President through the Secretary of Defense to the Combatant Commanders.