On August 9, the following notable historical events related to Missouri have been recorded:
- 1804: The Lewis and Clark Expedition was near present-day Council Bluffs, Iowa, across from Missouri’s Atchison County, on or around August 9. They continued documenting the region’s geography and interactions with Native American tribes, advancing their exploration of the Louisiana Purchase.
- 1838: During the Mormon War in Missouri, tensions remained high. On or around August 9, non-Mormon vigilantes in Daviess and Carroll Counties continued their campaign against Mormon settlers, with skirmishes escalating the conflict that led to the Mormon expulsion order later in 1838.
- 1861: During the Civil War, Missouri was a hotbed of conflict. On August 9, Union forces under General Nathaniel Lyon were in final preparations near Springfield, Missouri, for the Battle of Wilson’s Creek, which occurred the following day, marking a significant engagement in the state.
- 1870: The Kansas City Stockyards expanded operations around August 9, reinforcing Kansas City’s role as a major livestock trading hub and boosting Missouri’s agricultural economy.
- 1904: The St. Louis World’s Fair, or Louisiana Purchase Exposition, was ongoing, with August 9 featuring international cultural exhibits and early Olympic events, highlighting Missouri’s global prominence.
- 1945: On August 9, the atomic bomb was dropped on Nagasaki, and Missouri played a role in the war effort. The Monsanto Chemical Company in St. Louis had contributed to the Manhattan Project by producing key components, underscoring Missouri’s involvement in World War II.