January 14 – U.S. Secretary of the Treasury Alexander Hamilton submits his proposed plan for payment of American debts, starting with $12,000,000 to pay the foreign debts of the confederation, followed by $40 million for domestic debts, and $21.5 million for the war debts of the states. The plan was narrowly approved 14-12 in the Senate and 34-28 in the House.
March 4 – France is divided into 83 départements, which cut across the former provinces, in an attempt to dislodge regional loyalties based on noble ownership of land.
March 6 – The New York legislature consents to the admission to the Union of a new state, Vermont, formed within the boundaries of New York, contingent upon the successful conclusion of negotiations concerning disputed real-estate claims, and the boundary between the two states.
June 20 – Compromise of 1790: Thomas Jefferson, James Madison, and Alexander Hamilton come to an agreement: Madison agrees to not be "strenuous" in opposition for the assumption of state debts by the federal government; Hamilton agrees to support the capital site being above the Potomac.
July 10 — The U.S. House of Representatives votes, 32-29 to approve creating the District of Columbia from portions of Maryland and Virginia for the eventual seat of government and national capital.
July 16 – U.S. President George Washington signs the Residence Act into law, establishing a site along the Potomac River as the District of Columbia and the future site of the capital of the United States. The move comes after the bill is narrowly approved on July 1 by the Senate, 14 to 12, and on July 9 by the House, 32 to 29. At the same time, plans are made to move the national capital from New York to Philadelphia until the Potomac River site can be completed.
October 7 – Commissioners appointed by the New York legislature announce the successful conclusion of negotiations between New York and Vermont, concerning disputed real-estate claims, and the consent of New York's legislature to the admission to the Union of the state of Vermont as the 14th State (which was formed within what New York claimed as its territory, under an Order in Council, that King George III issued on July 20, 1764).