The Articles of Confederation took effect on March 1, 1781, after Maryland became the final state to ratify them.
Congress finalized the Articles on November 15, 1777, and sent them to the states for approval. Ratification took more than three years because Maryland withheld consent until states with western land claims agreed to transfer those claims to the United States.
Maryland ratified the Articles on February 2, 1781, and the Confederation Congress formally implemented them on March 1. The Articles created the first national governing framework for the United States and established a Congress of the Confederation, but they gave the central government limited powers.
The Articles remained in force until the Constitution replaced them on March 4, 1789. A frequent mix-up is treating November 15, 1777, as the effective date; that was the date Congress finalized the document, not the date the states' ratification process completed.