What was the first U.S. capital established under the Constitution?

New York City was the first U.S. capital established under the Constitution.

The new federal government began operating in New York City in 1789. Federal Hall on Wall Street served as the first Capitol, and George Washington was inaugurated there on April 30 of that year. New York therefore became the first national capital under the constitutional government.

Congress moved the capital to Philadelphia in 1790 under the Residence Act. Philadelphia remained the temporary capital for a decade while a permanent federal district was planned along the Potomac River. The government moved to Washington, D.C., in 1800.

New York City had also hosted the Congress of the Confederation before the Constitution took effect, but that earlier role is sometimes confused with its constitutional-capital status. The capital’s relocation reflected political compromise, including southern support for assuming state debts in exchange for placing the permanent capital farther south.