The June 14 date is when Congress adopted “the American continental army” after reaching a consensus position in The Committee of the Whole. This procedure and the desire for secrecy account for the sparseness of the official journal entries for the day. The record indicates only that Congress undertook to raise ten companies of riflemen, approved an enlistment form for them, and appointed a committee (including Washington and Schuyler) to draft rules and regulations for the government of the army.
Please stand;
There’s more at the Army Birthday website.
It’s also Flag Day and in Virginia it’s “HOV Lane Awareness Day”.
The ONLY service founded in 1775.