On August 17, the following notable historical events related to Missouri have been recorded:

• 1804: The Lewis and Clark Expedition was near present-day Omaha, Nebraska, across from Missouri’s Atchison County, on or around August 17. 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 17, 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, the aftermath of the Battle of Wilson’s Creek (August 10) was ongoing in Missouri. On August 17, Union forces were regrouping after their retreat from Springfield, while Confederate forces maintained their position in southwest Missouri, underscoring the state’s critical role in the conflict.
• 1876: The St. Louis-based Missouri Botanical Garden, founded by Henry Shaw, hosted a significant public exhibition around August 17, showcasing new plant species and reinforcing its status as a leading botanical research center.
• 1904: The St. Louis World’s Fair, or Louisiana Purchase Exposition, was ongoing, with August 17 featuring international scientific exhibits and early Olympic events, highlighting Missouri’s global cultural and economic prominence.
• 1964: The St. Louis Cardinals played a notable game against the Pittsburgh Pirates at Busch Stadium on August 17, with Lou Brock stealing two bases and contributing to a Cardinals victory, reinforcing Missouri’s baseball legacy during their World Series-winning season.