The US Army traces its founding to June 14, 1775, which is the date when the Second Continental Congress organized the militia forces in Boston and New York into a continental army to resist the British. The revolution itself had started in April of 1775 with the battles of Lexington and Concord, but the forces that were defending Boston and New York were state militia bodies. The adoption of the Declaration of Independence a bit over a year later followed from the fighting between British and colonial troops throughout 1775 and the early part of 1776; the Declaration followed the war, if that makes sense, not started it.