Portal:United States/Anniversaries/September/September 4
- 1781 – Los Angeles is founded as El Pueblo de Nuestra Señora La Reina de los Ángeles (The Village of Our Lady, the Queen of the Angels) by 44 Spanish settlers. (skyline pictured)
- 1862 – American Civil War Maryland Campaign: General Robert E. Lee takes the Army of Northern Virginia, and the war, into the North.
- 1882 – The Pearl Street Station in New York City becomes the first power plant to supply electricity to paying customers.
- 1923 – Maiden flight of the first U.S. airship, the USS Shenandoah.
- 1957 – American Civil Rights Movement: Little Rock Crisis: The governor of Arkansas calls out the National Guard to prevent African American students from enrolling in Little Rock Central High School, resulting in the lawsuit Cooper v. Aaron the following year.
- 1998 – Google is founded by Larry Page and Sergey Brin, two students at Stanford University.