New York City served as the first U.S. capital under the Constitution.
The new federal government began operating in New York City in 1789. Federal Hall on Wall Street hosted the first Congress, and George Washington took the presidential oath there on April 30, 1789.
New York was not the permanent capital. In 1790, the federal government moved to Philadelphia, which served as the capital for a decade. The Residence Act of 1790 provided for a permanent capital on the Potomac River.
Washington, D.C., became the national capital in 1800. Philadelphia had earlier served as a meeting place for the Continental Congress and the Constitutional Convention, which is why the cities can be confused when discussing the founding period.