The Continental Congress was a series of legislative bodies, with some executive function, for thirteen of Britain's colonies in North America, and the newly declared United States just before, during, and after the American Revolutionary War. The term "Continental Congress" most specifically refers to the First and Second Congresses of 17741781 and, at the time, was also used to refer to the Congress of the Confederation of 17811789, which operated as the first national government of the United States until being replaced under the Constitution of the United States. Thus, the term covers the three congressional bodies of the Thirteen Colonies and the new United States that met between 1774 and 1789.

The First Continental Congress was called in 1774 in response to growing tensions between the colonies culminating in the passage of the Intolerable Acts by the British Parliament. It met for about six weeks and sought to repair the fraying relationship between Britain and colonies, while asserting the rights of colonists, proclaiming and passing the Continental Association (a unified trade embargo against Britain), and calling for a second congress. The Second Continental Congress convened in 1775 in the wake of the breakout of hostilities in Massachusetts. Soon after meeting, this second Congress sent the Olive Branch Petition to King George III while also selecting George Washington as the head of the new Continental Army. After peace was not forthcoming, the same congress drafted and adopted the Independence resolution and the Declaration of Independence in July 1776, proclaiming that the former colonies were now independent sovereign states.

The Second Continental Congress served as the provisional government of the U.S. for most of the War of Independence. In March 1781, the nation's first Frame of Government, the Articles of Confederation and Perpetual Union, came into force, at which time the body became what later was called the Congress of the Confederation. This unicameral governing body would convene in eight sessions before adjourning in 1789, when the 1st United States Congress under the new Constitution of the United States took over the role as the nation's legislative branch of government.

Both the First and Second Continental Congresses convened in Philadelphia, though with the city's capture during the Revolutionary War, the Second Congress was forced to meet in other locations for a time. The Congress of Confederation was also established in Philadelphia and later moved to New York City which served as the U.S. capital from 1785 to 1790.

Much of what is known today about the daily activities of these congresses comes from the journals kept by the secretary for all three congresses, Charles Thomson. Printed contemporaneously, the Journals of the Continental Congress contain the official congressional papers, letters, treaties, reports and records. The delegates to the Continental and Confederation congresses had extensive experience in deliberative bodies, with "a cumulative total of nearly 500 years of experience in their Colonial assemblies, and fully a dozen of them had served as speakers of the houses of their legislatures."

The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, secured a United States of America independent from Great Britain. Fighting began on April 19, 1775, followed by the Declaration of Independence on July 4, 1776. The American Patriots were supported by France and Spain, conflict taking place in North America, the Caribbean, and Atlantic Ocean. It ended on September 3, 1783 when Britain accepted American independence in the Treaty of Paris, while the Treaties of Versailles resolved separate conflicts with France and Spain.Established by Royal charter in the 17th and 18th centuries, the American colonies were largely autonomous in domestic affairs and commercially prosperous, trading with Britain and its Caribbean colonies, as well as other European powers via their Caribbean entrepôts. After British victory in the Seven Years' War in 1763, tensions arose over trade, colonial policy in the Northwest Territory and taxation measures, including the Stamp Act and Townshend Acts. Colonial opposition led to the 1770 Boston Massacre and 1773 Boston Tea Party, with Parliament responding by imposing the so-called Intolerable Acts.

On September 5, 1774, the First Continental Congress drafted a Petition to the King and organized a boycott of British goods. Despite attempts to achieve a peaceful solution, fighting began with the Battle of Lexington on April 19, 1775 and in June Congress authorized George Washington to create a Continental Army. Although the "coercion policy" advocated by the North ministry was opposed by a faction within Parliament, both sides increasingly viewed conflict as inevitable. The Olive Branch Petition sent by Congress to George III in July 1775 was rejected and in August Parliament declared the colonies to be in a state of rebellion.

Following the loss of Boston in March 1776, Sir William Howe, the new British commander-in-chief, launched the New York and New Jersey campaign. He captured New York City in November, before Washington won small but significant victories at Trenton and Princeton, which restored Patriot confidence. In summer 1777, Howe succeeded in taking Philadelphia, but in October a separate force under John Burgoyne was forced to surrender at Saratoga. This victory was crucial in convincing powers like France and Spain an independent United States was a viable entity.

France provided the US informal economic and military support from the beginning of the rebellion, and after Saratoga the two countries signed a commercial agreement and a Treaty of Alliance in February 1778. In return for a guarantee of independence, Congress joined France in its global war with Britain and agreed to defend the French West Indies. Spain also allied with France against Britain in the Treaty of Aranjuez (1779), though it did not formally ally with the Americans. Nevertheless, access to ports in Spanish Louisiana allowed the Patriots to import arms and supplies, while the Spanish Gulf Coast campaign deprived the Royal Navy of key bases in the south.

This undermined the 1778 strategy devised by Howe's replacement, Sir Henry Clinton, which took the war into the Southern United States. Despite some initial success, by September 1781 Cornwallis was besieged by a Franco-American force in Yorktown. After an attempt to resupply the garrison failed, Cornwallis surrendered in October, and although the British wars with France and Spain continued for another two years, this ended fighting in North America. In April 1782, the North ministry was replaced by a new British government which accepted American independence and began negotiating the Treaty of Paris, ratified on September 3, 1783.