1st United States Congress

The 1st United States Congress, comprising the United States Senate and the United States House of Representatives, met from March 4, 1789, to March 4, 1791, during the first two years of George Washington's presidency, first at Federal Hall in New York City and later at Congress Hall in Philadelphia. With the initial meeting of the First Congress, the United States federal government officially began operations under the new (and current) frame of government established by the 1787 Constitution.

Source: Wikipedia — 1st United States Congress (CC BY-SA 4.0)