I worked for the Army for the last 4 years, and I have a degree in history concentrating on military history. My kids were in the Army. The US Army's roots were in the Continental Army. The Army celebrates its birthday on June 14th each year.
"the modern U.S. Army has its roots in the
Continental Army, which was formed 14 June 1775 to fight the
American Revolutionary War (1775–1783)—before the United States was established as a country."
en.wikipedia.org
I was once honored to attend the Army's birthday celebration at the Army War College in Carlisle Barracks, PA, with my daughter who was an Army ROTC cadet at the time.