The Continental Army spent five years trying to look like an army. It mostly got there in the sixth.
Quick answer. The Continental Army uniform was formalised by Washington's regulation of 1779: dark blue coat with regional facings (white for New England, red for Mid Atlantic, blue for Southern, buff for staff), white waistcoat, white or buff breeches, long black gaiters, tricorne or round hat. Before 1779 the dress was improvised, often hunting shirts or civilian clothes. The French subsidy of 1778 made the regular uniform possible.
The 1775 to 1778 period
When Washington took command of the army outside Boston in July 1775, he found an improvised force of New England militia in civilian clothes. The Continental Congress had no money for uniforms. Soldiers wore whatever they had. Washington ordered the use of hunting shirts in 1776: cheap linen or deerskin pullovers that gave the army a semblance of common dress. The hunting shirt was fringed, often dyed brown or green, and worn over the shirt and under a cross belt. It became the signature Continental item of the early war.
Washington himself wore a dark blue coat with buff facings, his personal choice as a Virginia officer, which anticipated the later regulation.
The French supply
France entered the war in 1778, bringing not only military and naval support but massive supplies of cloth and manufactured goods. Dark blue French wool arrived in large quantities. By late 1778 enough material existed to begin uniforming the Continental Army in a consistent pattern. Washington issued his order on 2 October 1779 setting dark blue as the standard colour and specifying regional facings for identification.
The 1779 regulation
The 1779 regulation specified: dark blue wool coat, cut in the British 1768 pattern with lapels buttoned back to show the facing colour, buttons bearing USA in the US Army style. Facings varied by region. New England regiments: white. Mid Atlantic (New York, New Jersey, Pennsylvania): red. Southern (Virginia, Maryland, North and South Carolina, Georgia): blue. Staff and general officers: buff. Light infantry: specific additions including a tall feather. Artillery: red facings. The whole scheme allowed battlefield identification of friendly troops by region.
Officers' dress
Continental officers wore the same regimental coat as their men but of finer cloth. Rank was shown by a specific pattern of silk cockade on the hat (field officers red, captains yellow or buff, subalterns green) and later by silver or gold epaulettes. The sash was crimson silk, as in the British army. Officers wore boots instead of gaiters. They paid for their own uniforms, which created problems: many officers resigned over the inability to afford new clothes as prices inflated through the war.
The dragoons and marines
The Continental Light Dragoons (four regiments) wore various uniforms including dark blue with white or red facings, leather or metal helmets with crests, and long boots. The dragoons were small formations but famous for their raids, especially Henry Lee's Legion in the Southern campaign. The Continental Marines, raised in 1775, wore green coats with white facings for the first American marine uniform.
The Southern army and the end of the war
The Southern army under Nathanael Greene from 1780 was poorly uniformed compared to Washington's main army in the North. Supply problems, long distances and the campaign tempo meant many Southern soldiers remained in hunting shirts or captured British uniforms through 1781. By Yorktown in October 1781, the regular Continental regiments present were in correct 1779 pattern uniforms, while militia and some irregulars continued in whatever they had.
Common questions
When was the Continental Army uniform standardised?
October 1779, by Washington's general order. The regulation was finally possible because French cloth supplies had arrived in large quantities.
What colour was Washington's coat?
Dark blue with buff facings. This was Washington's personal choice as a Virginia officer and anticipated the later staff officers' pattern.
Did soldiers really wear hunting shirts?
Yes. The hunting shirt was in widespread use from 1775 to 1778 and continued in militia use throughout the war.
Where did the Continental Army get its uniforms?
Mostly from France after 1778. Earlier, from local workshops, Captured British supplies and anywhere else they could be found.
Can I buy a replica Continental uniform?
Yes. Reenactor tailors build full 1779 pattern coats in dark blue wool with proper regional facings.