The United States Army is the land warfare service branch of the U.S. Armed Forces. It is the oldest and most senior branch of the U S military. The modern U.S. Army has its roots in the Continental Army, which was formed 14 June 1775 to fight the American Revolutionary War, before the United States of America was established as a country. The United States Army considers itself descended from the Continental Army, and dates its institutional inception from the origin of that armed force in 1775.