New York City was the first capital of the United States under the Constitution.
The new federal government began operating in New York City in 1789. Congress met in Federal Hall on Wall Street, where George Washington took the presidential oath on April 30, 1789. The city therefore served as the national capital when the Constitution’s government first began.
Philadelphia became the temporary capital in 1790 under the Residence Act and remained the seat of government for the next decade. The permanent capital, Washington, D.C., opened in 1800. This sequence differs from the earlier Revolutionary period, when Congress met in several cities, including Philadelphia, Baltimore, York, Lancaster, Princeton, Annapolis, and Trenton.
New York City’s role is sometimes overlooked because Washington, D.C., is now the capital and Philadelphia hosted the Constitutional Convention. The question specifies the capital under the Constitution’s new federal government, making New York City the precise answer.