Revolutionary War, American, the war in which 13 British colonies in North America won their freedom and became the United States of America. The colonies were Connecticut, Delaware, Georgia, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, and Virginia.

The war began at Lexington and Concord in Massachusetts on April 19, 1775. It was not formally ended until eight years later, September 3, 1783. The fighting was not continuous, however, and there were no major battles after 1781. Compared to those of 20th-century wars, casualties were light; only 4,000 American battle deaths were recorded.

Revolutionary War icons:Revolutionary War icons: General Washington with Lafayette at Valley Forge.

In the 1770's the 13 colonies had a population of 2,500,000less than one-third that of Great Britain. It has been estimated that only one-third of the colonists were active patriots, a third remained loyal to Britain, and the rest were neutral. The Americans, lacking an effective national government, had no satisfactory means of raising an army and had to rely on short-term enlistments. The Continental Army never exceeded 35,000 men at any one time and usually had fewer than 10,000 men fit for fighting. They were sometimes aided by militia, but this support was often unreliable. In battle, the Americans often faced numerical odds of four to one.

The Americans had the advantage of fighting on home ground, while the British had to transport troops and supplies across 3,000 miles (4,800 km) of ocean, a voyage of two or three months. The British government, dominated by corrupt and incompetent ministers, mismanaged the war from the beginning. American military leaders were mostly amateurs, but they were able to equal and often surpass the British professionals. British troops, although better trained, disciplined, and equipped, lacked the fighting spirit of the Americans; this was especially true of the 30,000 German soldiers (mostly Hessians) hired by Great Britain. The colonies lacked the resources to win the war without aid, but gained a powerful ally in France.

The war cost Great Britain a large part of its colonial empire, but this loss soon was offset by development of a new British empire in India, the Pacific, and Africa. Although less influential on European affairs than the French Revolution (1789), the American Revolution was nonetheless a turning point in history for it marked the beginnings of a new world power.