When did the U.S. Army officially begin?

The U.S. Army officially began on June 14, 1775. This date marks the establishment of the Continental Army, which was created by the Second Continental Congress to fight against British forces during the American Revolutionary War. This decision was pivotal because it organized colonial forces into a unified military structure, allowing for more coordinated and effective resistance against British rule.

The other options represent significant events in American history but do not signify the official establishment of the Army. July 4, 1776, is recognized for the adoption of the Declaration of Independence, which declared the colonies' intention to separate from Britain. April 15, 1783, is associated with the end of the Revolutionary War, while September 17, 1787, is when the U.S. Constitution was signed, outlining the framework of the government but not directly tied to the creation of the Army. Thus, June 14, 1775, is the correct date that marks the formal inception of the U.S. Army.