On September 11, the following notable historical events related to Missouri occurred:

• 1806: The Lewis and Clark Expedition was in the St. Louis area on or around September 11, nearing the conclusion of their exploration of the Louisiana Purchase, with St. Louis serving as their final destination.
• 1857: The Mountain Meadows Massacre, involving Missouri-connected Mormon militia, occurred on September 11 in Utah. While not in Missouri, the event tied back to tensions from the Missouri Mormon War (1838), influencing the state’s historical narrative.
• 1861: During the Civil War, the First Battle of Lexington was ongoing in Missouri. On or around September 11, Confederate forces under Sterling Price continued their advance on Lexington, besieging Union troops in a key early conflict.
• 1883: The Missouri Pacific Railroad expanded its network through southwest Missouri around September 11, connecting Springfield to other regions and boosting the state’s economic infrastructure.
• 1939: The Great Depression lingered in Missouri, and on or around September 11, federal New Deal programs funded the construction of public buildings in St. Louis, providing jobs and stimulating the local economy.
• 2001: The September 11 terrorist attacks had a profound impact on Missouri. St. Louis and Kansas City held vigils, and Missouri National Guard units were mobilized for security, reflecting the state’s response to the national tragedy.