January 27 - Fire breaks out in the sealed Apollo 1 space capsule during pre-flight simulation and kills astronauts Gus Grisson, Edward White and Roger Chaffee.
February 10 - The 25th Amendment to the U.S. Constitution goes into effect and specifies the fulfillment of vacancies in the Presidential or Vice Presidential Office during the term.
March 20 - The first U.S. Army General to die in Vietnam is A. J. F. Moody.
August 30 - Thurgood Marshall is confirmed as the first African American Supreme Court Justice.
November 20 - U.S. population reaches 200 million.
December 28 - Muriel Siebert is the first women to own a seat on the New York Stock Exchange.