United States: vacancy: 4 Mar 1789 - 30 Apr 1789

According to the provisions of the Constitution of 1787, federal Congress met on 4 Mar 1789 in New York City, but it could not proceed with any business as the number of delegates was insufficient for quorum.

The delegates continued to arrive in New York until the House of Representatives reached quorum on 1 Apr 1789, and elected Speaker, Frederick Augustus Muhlenberg, who became a highest state officer.

The Senate of the United States, in its turn, achieved quorum on 6 Apr 1789. John Langdon was elected President pro tempore "for the sole purpose of opening and counting the votes for President of the United States." John Adams, elected first Vice President and entitled to serve as a presiding officer of the Senate, was introduced by John Langdon to the chair of the house on 21 Apr 1789. First president of the United States, George Washington, was inaugurated on 30 Apr 1789.