The U.S. Pacific Command was established as a unified command on January 1, 1947, and it is the oldest and largest of the United States' unified commands.

The present U.S. Pacific Command (USPACOM) includes areas originally assigned to two other unified commanders. Responsibilities of the Far East Command were assumed on July 1, 1957. That same day the command assumed some of the responsibilities of the Alaskan Command, and individual Army and Air Force component commands for the Pacific were established in Hawaii.