It was also done to bring together people from all over to join the fight rather than have it be seen as a local rift.
The "expert riflemen" authorized on 14 June were the first units raised directly as Continentals. Congress intended to have the ten companies serve as a light infantry force for the Boston siege. At the same time it symbolically extended military participation beyond New England by allocating 6 of the companies to Pennsylvania, 2 to Maryland, and 2 to Virginia. Each company would have a captain, 3 lieutenants, 4 sergeants, 4 corporals, a drummer (or horn player), and 68 privates...
The inclusion of troops from outside New England gave a continental flavor to the army at Boston. A desire to broaden the base of support for the war also led John Adams to work for the appointment of a southerner as the commander of all the continental forces, raised, or to be raised, for the defense of American liberty...
Although sectional politics were involved in Washington's selection, in strictly military terms he was in fact the best-qualified native American. He had begun his military career in 1752 in the Virginia militia as one of four regional adjutants responsible for training. During the first phase of the French and Indian War, he served with gallantry as Edward Braddock's volunteer aide at the battle of the Monongahela, and later as the commander of Virginia's two Provincial regiments defending the colony's frontiers. In 1758 he commanded a brigade composed of Virginia, Maryland, and Pennsylvania units on John Forbes' expedition against Fort Duquesne. Washington was the only American in that war to command so large a force. The experience of these years taught him the importance of discipline, marksmanship, and professional study.