The notion of the Thirteen American Colonies become independent States was first broached by Richard Henry Lee in a resolution he presented to Congress on June 7, 1776. The resolution, which was approved on July2, stated that “That these United Colonies are, and of right ought to be, free and independent States.” This concept was embodied in the Declaration of Independence, which was described as the “unanimous Declaration of the thirteen United States of America.”
But three months would elapse before Congress would make the change from “Colonies” to “States” official.
On September 9, 1776, Congress issued another, less-famous Declaration stating that “in all continental commissions, and other instruments, where, heretofore, the words ‘United Colonies’ have been used, the stile [sic] be altered for the future to the ‘United States.’”
One class of those “instruments” was the property of the Continental Army, and soon the initials “US” began to appear on various types of ordnance, supplies, and equipment as proof that they belong to the government of the United States of America. For their part, Soldiers began to wear pewter buttons engraved with the intertwined letters “USA.” By 1800, the “USA” had been shortened to simply “US” or “U.S.”
In 1851, the letters “US” were designated as uniform insignia to be worn on officers’ hat bands, specifically those of generals and staff officers. Today, the letters appear on a disc for enlisted personnel’s collar insignia, and in block letter form for wear by officers.