AP US History This Day in American History September 3 1777 – The American flag was flown in battle for the first time during a Revolutionary War skirmish at Cooch's Bridge, Delaware.

AP US History This Day in American History September 3 1861 – Confederate General Leonidas Polk commits a major political blunder by marching his troops into Columbus, Kentucky–negating Kentucky's avowed neutrality and causing the Unionist legislature to invite the U.S. government to drive the invaders away.

AP US History This Day in American History September 3 1855 - General William Harney and 700 soldiers take revenge for the Grattan Massacre with a brutal attack on a Sioux village in Nebraska that left 100 men, women, and children dead.

AP US History This Day in American History September 3 1919 – President Woodrow Wilson embarks on a tour across the United States to promote American membership in the League of Nations, an international body that he hoped would help to solve international conflicts and prevent another bloody world war.