On June 3, the following notable historical events related to Missouri have been recorded:

• 1804: The Lewis and Clark Expedition was in the St. Louis area on or around June 3, completing final preparations and gathering supplies for their journey up the Missouri River to explore the Louisiana Purchase, reinforcing Missouri’s role as a starting point for western exploration.
• 1820: Missouri’s constitutional convention, convened in St. Louis, continued drafting the state’s first constitution around June 3. This was a critical step toward Missouri’s admission as a state in 1821, amidst debates over slavery as part of the Missouri Compromise.
• 1861: During the Civil War, Missouri was marked by rising tensions. On or around June 3, Union forces under General Nathaniel Lyon were securing St. Louis, conducting operations to prevent Confederate sympathizers from gaining control of key infrastructure like the St. Louis Arsenal.
• 1874: The Missouri Pacific Railroad expanded its network through central Missouri around June 3, completing a key line connecting Jefferson City to St. Louis, enhancing the state’s transportation and economic growth.
• 1904: The St. Louis World’s Fair, or Louisiana Purchase Exposition, was in its early stages, with June 3 featuring international trade exhibits and cultural performances, showcasing Missouri’s global prominence.
• 1964: The St. Louis Cardinals played a significant game against the Pittsburgh Pirates at Busch Stadium on June 3, with Bob Gibson pitching a complete game and contributing to a Cardinals victory, reinforcing Missouri’s baseball legacy.