1775 The United States Congress adopts the Olive Branch Petition.
1789 The United States Congress passes the Judiciary Act which creates the office of the United States Attorney General and the federal judiciary system, and orders the composition of the Supreme Court of the United States.
1800 The United States Congress holds its first session in Washington, D.C.
1818 The United States Congress adopts the flag of the United States with 13 red and white stripes and one star for each state (then 20).
1865 American Civil War: The United States Congress passes the Thirteenth Amendment to the Constitution of the United States, abolishing slavery, submitting it to the states for ratification.
1942 Queen Wilhelmina of the Netherlands becomes the first reigning queen to address a joint session of the United States Congress.
1945 The United States Congress officially recognizes the Pledge of Allegiance.
1952 The U.S. non-incorporated colonial territory of Puerto Rico adopts a "constitution" of local-limited powers, approved by the United States Congress in contravention of then-current international law.
1991 Queen Elizabeth II of the United Kingdom of Great Britain and Northern Ireland addressed a joint session of the United States Congress. She is the first British monarch to address the U.S. Congress.