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).
1820 The U.S. Congress passes the Missouri Compromise.
1846 The Smithsonian Institution is chartered by the United States Congress after James Smithson donates $500,000.
1861 American Civil War: The United States Congress passes the Crittenden-Johnson Resolution, stating that the war is being fought to preserve the Union and not to end slavery.
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.
1866 The United States Congress passes legislation authorizing the five-star rank of General of the Army. Lieutenant General Ulysses S. Grant becomes the first to be promoted to this rank.
1900 The Congress passes the Foraker Act, giving Puerto Rico limited self-rule.
1901 US President Theodore Roosevelt delivers a 20,000-word speech to the House of Representatives asking the Congress to curb the power of trusts "within reasonable limits".
1930 Great Depression: US President Herbert Hoover goes before the United States Congress and asks for a US$150 million public works program to help generate jobs and stimulate the economy.
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.
1959 First United States Congress elections in Hawaii as a state of the Union.
1961 Apollo program: U.S. President John F. Kennedy announces before a special joint session of the Congress his goal to initiate a project to put a "man on the Moon" before the end of the decade.
1966 U.S. President Lyndon B. Johnson, responding to a sniper attack at the University of Texas at Austin, writes a letter to Congress urging the enactment of gun control legislation.
1983 Cold War: Korean Air Flight 007 is shot down by a Soviet Union jet fighter when the commercial aircraft enters Soviet airspace. All 269 on board die, including Congressman Lawrence McDonald.
1985 Tipper Gore and other political wives form the Parents Music Resource Center as Frank Zappa and other musicians testify at U.S. Congressional hearings on obscenity in rock music.
1989 The U.S. Supreme Court rules that a law passed by the U.S. Congress banning all sexually oriented phone message services is unconstitutional.
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.
2002 Antonio Meucci is acknowledged as the first inventor of the telephone by the United States Congress.