July 21 is the 202nd day (203rd in leap years) of the year in the Gregorian Calendar, with 163 days remaining.
- 1298 - Battle of Falkirk (1298): England's Edward Longshank defeats William Wallace's Scottish rebels
- 1568 - Battle of Jemmingen: Fernando Álvarez de Toledo, Duke of Alva defeats Louis of Nassau
- 1718 - Treaty of Passarowitz signed.
- 1774 - Russia and the Ottoman Empire sign the Treaty of Kuchuk-Kainarji ending the Russo-Turkish War, 1768-74.
- 1831 - Inauguration of Leopold I of Belgium, first king of the Belgians.
- 1861 - American Civil War: First Battle of Bull Run - At Manassas Junction, Virginia, the first major battle of the war begins (Confederate victory).
- 1865 - In the market square of Springfield, Missouri, Wild Bill Hickok shoots Dave Tutt dead in what is regarded as the first true western showdown.
- 1873 - At Adair, Iowa, Jesse James and the James-Younger gang pull off the first successful train robbery in the American West.
- 1877 - After rioting by Baltimore and Ohio Railroad workers and the deaths of 9 rail workers at the hands of the Maryland militia, workers in Pittsburgh stage a sympathy strike that is met with an assault by the state militia.
- 1925 - Scopes Trial: In Dayton, Tennessee, high school biology teacher John T. Scopes is found guilty of teaching evolution in class and fined $100.
- 1931 - CBS's New York City station begins broadcasting the first regular seven days a week television schedule in the U. S.
- 1944 - World War II: Battle of Guam - American troops land on Guam starting the battle (ends on August 10).
- 1954 - First Indochina War: The Geneva Conference partitions Vietnam into North Vietnam and South Vietnam.
- 1961 - Mercury program: Gus Grissom piloting the Mercury 4 capsule "Liberty Bell 7" becomes the second American to go into orbit around the Earth.
- 1963 - Pope Paul VI elected by College of Cardinals.
- 1970 - After 11 years of construction, the Aswan High Dam in Egypt is completed.
- 1984 - In Jackson, Michigan, a factory robot crushes a worker against a safety bar in apparently the first robot-related death in the United States.
- 1995 - Third Taiwan Strait Crisis: The People's Liberation Army begins firing missiles into the waters north of Taiwan.
- 1997 - The fully restored USS Constitution (aka "Old Ironsides") celebrates her 200th birthday by setting sail for the first time in 116 years.
- 2002 - Telecom giant WorldCom files for Chapter 11 bankruptcy protection in the largest such filing in United States history.
- 2004 - The United Kingdom government publishes Delivering Security in a Changing World, a paper detailing wide-ranging reform of the country's armed forces.
- 1414 - Pope Sixtus IV
- 1810 - Henri Victor Regnault, chemist and physicist
- 1858 - Lovis Corinth, painter and graphic artist (d. 1925)
- 1870 - Emil Orlik, painter and graphic artist (d. 1932)
- 1893 - Hans Fallada, writer (d. 1947)
- 1899 - Hart Crane, poet (d. 1932)
- 1899 - Ernest Hemingway, author (d. 1961)
- 1903 - Roy Neuberger, financier & art collector
- 1911 - Marshall McLuhan, author (d. 1980)
- 1920 - Isaac Stern, violinist (d. 2001)
- 1924 - Don Knotts, actor
- 1925 - Anne Meacham, Broadway and television actress
- 1926 - Norman Jewison, film director
- 1933 - John Gardner, author (d. 1982)
- 1935 - Norbert Blüm, German politician
- 1938 - Janet Reno, former Attorney General of the United States
- 1943 - Edward Herrmann, actor
- 1944 - Tony Scott, film director
- 1944 - Paul Wellstone, U.S. Senator: Democrat from Minnesota (d. 2002)
- 1948 - Ed Hinton, sportswriter
- 1948 - Cat Stevens (Yusuf Islam), singer
- 1948 - Garry Trudeau, cartoonist
- 1952 - Robin Williams, comedian
- 1957 - Jon Lovitz, comedian
- 1968 - Brandi Chastain, American soccer player
- 1968 - Lyle Odelein, Hockey Player
- 1978 - Josh Hartnett, actor
- 1425 - Manuel II Palaeologus, Byzantine Emperor
- 1796 - Robert Burns, poet (b. 1759)
- 1833 - Robert G. Ingersoll, American political leader and orator, atheist, American Civil War Colonel
- 1870 - Josef Strauss, composer
- 1938 - Owen Wister, author
- 1943 - Charlie Paddock, American athlete
- 1948 - David Wark Griffith, film director
- 1967 - Jimmie Foxx, Baseball Hall of Famer
- 1967 - Basil Rathbone, actor
- 1968 - Ruth St. Denis, dancer, choreographer
- 1972 - Ralph Craig, American athlete
- 1982 - Dave Garroway, television host
- 1998 - Alan Shepard, astronaut
- 1998 - Robert Young, actor
- 2004 - Elder Neal A. Maxwell, member of the Quorum of the Twelve Apostles of The Church of Jesus Christ of Latter-day Saints
Holidays and observances
July 20 - July 22 - June 21 - August 21 -- listing of all days
ca:21 de juliol
es:21 de julio
eo:21-a de julio
oc:21 de julhet
pt:21 de Julho