The Congress of the Confederation, or the Confederation Congress, formally referred to as the United States in Congress Assembled, was the governing body of the United States from March 1, 1781, until March 3, 1789, during the Confederation period. A unicameral body with legislative and executive function, it was composed of delegates appointed by the legislatures of the several states. Each state delegation had one vote. The Congress was created by the Articles of Confederation and Perpetual Union upon its ratification in 1781, formally replacing the Second Continental Congress.

The Articles of Confederation and Perpetual Union was an agreement among the 13 states of the United States, formerly the Thirteen Colonies, that served as the nation's first frame of government. It was debated by the Second Continental Congress at Independence Hall in Philadelphia between July 1776 and November 1777, and finalized by the Congress on November 15, 1777. It came into force on March 1, 1781, after being ratified by all 13 colonial states. A guiding principle of the Articles was the establishment and preservation of the independence and sovereignty of the states. The Articles consciously established a weak federal government, affording it only those powers the former colonies had recognized as belonging to king and parliament. The document provided clearly written rules for how the states' league of friendship, known as the Perpetual Union, would be organized.