Washington initially protested enlistment of slaves in the Continental Army, but later he relented when the British emancipated and used theirs. On January 16, 1776, Congress allowed free blacks to serve in the militia. By the end of the war one-tenth of Washington's army were blacks.
On March 17, 9,000 British troops and Loyalists began a chaotic ten-day evacuation of Boston aboard 120 ships. Soon after, Washington entered the city with 500 men, with explicit orders not to plunder the city. He ordered vaccinations against smallpox to great effect, as he did later in Morristown, New Jersey.
Washington then proceeded to New York City, arriving on April 13, 1776, and began constructing fortifications there to thwart the expected British attack. He ordered his occupying forces to treat civilians and their property with respect, to avoid the abuse suffered by civilians in Boston at the hands of British troops.
At the time of the Declaration of Independence in July 1776, the Continental Congress would not legally adopt flags with "stars, white in a blue field" for another year. The flag contemporaneously known as "the Continental Colors" has historically been referred to as the first national flag.
Howe's pursuit forced Washington to retreat across the Hudson River to Fort Lee to avoid encirclement. Howe landed his troops on Manhattan in November and captured Fort Washington, inflicting high casualties on the Americans. Washington was responsible for delaying the retreat, though he blamed Congress and General Greene. Loyalists in New York considered Howe a liberator and spread a rumor that Washington had set fire to the city. Patriot morale reached its lowest when Lee was captured.
Washington crossed the Delaware River at sunset on Christmas Day, December 25, 1776, and risked capture staking out the Jersey shoreline. His men followed across the ice-obstructed river in sleet and snow at McKonkey's Ferry, with 40 men per vessel. Wind churned up the waters, and they were pelted with hail, but by 3:00 a.m. they made it across with no losses.