| 106231 | September 17 | Event | 1716 – Jean Thurel enlists in the Touraine Regiment at the age of 18, the first day of a military career that would span for over 90 years. |
| 106232 | September 17 | Event | 1761 – The Battle of Kosabroma is fought. |
| 106233 | September 17 | Event | 1775 – American Revolutionary War: The Invasion of Canada begins with the Siege of Fort St. Jean. |
| 106234 | September 17 | Event | 1776 – The Presidio of San Francisco is founded in New Spain. |
| 106235 | September 17 | Event | 1778 – The Treaty of Fort Pitt is signed. It is the first formal treaty between the United States and a Native American tribe (the Lenape or Delaware Indians). |
| 106236 | September 17 | Event | 1787 – The United States Constitution is signed in Philadelphia. |
| 106237 | September 17 | Event | 1793 – The Battle of Peyrestortes is fought. |
| 106238 | September 17 | Event | 1794 – The Battle of Sprimont is fought. |
| 106239 | September 17 | Event | 1809 – Peace between Sweden and Russia in the Finnish War. The territory to become Finland is ceded to Russia by the Treaty of Fredrikshamn. |
| 106240 | September 17 | Event | 1813 – The Second Battle of Kulm is fought. |
| 106241 | September 17 | Event | 1814 – Francis Scott Key finishes his poem "Defence of Fort McHenry", later to be the lyrics of "The Star-Spangled Banner". |
| 106242 | September 17 | Event | 1849 – American abolitionist Harriet Tubman escapes from slavery. |
| 106243 | September 17 | Event | 1859 – Joshua A. Norton declares himself "Norton I, Emperor of the United States." |
| 106244 | September 17 | Event | 1861 – Battle of Pavón is fought. |
| 106245 | September 17 | Event | 1862 – American Civil War: George B. McClellan halts the northward drive of Robert E. Lee's Confederate Army in the single-day Battle of Antietam, the bloodiest day in American military history. |
| 106246 | September 17 | Event | 1862 – American Civil War: The Allegheny Arsenal explosion results in the single largest civilian disaster during the war. |
| 106247 | September 17 | Event | 1894 – Battle of the Yalu River, the largest naval engagement of the First Sino-Japanese War. |
| 106248 | September 17 | Event | 1900 – Philippine–American War: Filipinos under Juan Cailles defeat Americans under Colonel Benjamin F. Cheatham Jr., son of confederate general Benjamin F. Cheatham in the Battle of Mabitac. |
| 106249 | September 17 | Event | 1901 – The Battle of Blood River Poort is fought. |
| 106250 | September 17 | Event | 1901 – The Battle of Elands River is fought. |
| 106251 | September 17 | Event | 1908 – The Wright Flyer flown by Orville Wright, with Lieutenant Thomas Selfridge as passenger, crashes, killing Selfridge. He becomes the first airplane fatality. |
| 106252 | September 17 | Event | 1914 – Andrew Fisher becomes Prime Minister of Australia for the third time. |
| 106253 | September 17 | Event | 1914 – World War I: The Race to the Sea begins. |
| 106254 | September 17 | Event | 1916 – World War I: Manfred von Richthofen ("The Red Baron"), a flying ace of the German Luftstreitkräfte, wins his first aerial combat near Cambrai, France. |
| 106255 | September 17 | Event | 1924 – The Border Protection Corps is established in the Second Polish Republic for the defence of the eastern border against armed Soviet raids and local bandits. |
| 106256 | September 17 | Event | 1924 – The Church of Central Africa Presbyterian is formed. |
| 106257 | September 17 | Event | 1928 – The Okeechobee hurricane strikes southeastern Florida, killing more than 2,500 people. It is the third deadliest natural disaster in United States history, behind the Galveston hurricane of 1900 and the 1906 San Francisco earthquake. |
| 106258 | September 17 | Event | 1930 – The Ararat rebellion is suppressed. |
| 106259 | September 17 | Event | 1932 – A speech by Laureano Gómez leads to the escalation of the Leticia Incident. |
| 106260 | September 17 | Event | 1939 – World War II: The Soviet Union joins Nazi Germany's invasion of Poland during the Polish Defensive War of 1939. |