The US Army is Older than the United States

  The official birthday of the United States is July 4th 1776, but the Army was formed in 1775. the reason for this is that before we became a nation we needed an organized military in order to remove ourselves from the dominion of the British.
The establishment of the Army was necessary if there were ever going to be any chance of independence from the British. Each State had an established militia which equated to a group of ill trained ill equipped volunteers who serve out of a sense of patriotism and obligation. they were not very well organized at all and were little match for the well trained, experienced, and well disciplined British Army.
The militia's didn't really have a structure or chain of command so if they had not been organized into an Army there is no way they would have been able to stand against the British.
Now if you allow me to be perfectly honest I don't believe that the Continental Army would have been able to stand against the British if they had not had such a long logistics train. They had to keep their Army resupplied from across the Atlantic Ocean. Food and some materials were obtainable here, but reinforcements had to come from across the ocean. They did make use of escaped and former slaves and anyone else that they could get to pledge allegiance in the fight against the colonies but it was not enough.
The official date of the Army's birth was June 14th 1774. It was done through a resolution which was made by the Continental Congress.
George Washington became the first Commander in Chief with the daunting task of organizing the rag tag forces into a formidable force. this elevated his leadership and made him the natural choice to become the first President of the United States. Military Commemorative Rings