George Washington took the first presidential oath under the Constitution on April 30, 1789.
The ceremony took place at Federal Hall in New York City, then the nation’s capital. Chancellor Robert Livingston administered the oath, and Washington added the words “so help me God,” according to the traditional account, although historians debate whether that phrase appeared in the contemporary record.
Washington’s inauguration followed the first presidential election under the Constitution. The Electoral College selected him unanimously, while John Adams became vice president after receiving the second-highest electoral vote.
The date is easy to confuse with March 4, 1789, when the new constitutional government officially began operating and the First Congress met. Washington’s actual inauguration occurred nearly two months later.