The Department of the Army (DA) is one of the three military departments within the Department of Defense of the United States of America. Its mission is to fight and win our Nation’ s wars by p...view moreThe Department of the Army (DA) is one of the three military departments within the Department of Defense of the United States of America. Its mission is to fight and win our Nation’ s wars by providing prompt, sustained land dominance across the full range of military operations and spectrum of conflict in support of combatant commanders.view less