4th Missouri Infantry Regiment (Union, 3 months)

The 4th Missouri Infantry Regiment evolved from one of several unofficial pro-Unionist militia units formed semi-secretly in St. Louis in the early months of 1861 by Congressman Francis Preston Blair Jr. and other Unionist activists.

The organization that would become the Fourth Missouri was largely composed of ethnic Germans, who were generally opposed to slavery and strongly supportive of the Unionist cause.

Although initially without any official standing, beginning on April 22, 1861, four militia regiments Blair helped organize were sworn into Federal service at the St. Louis Arsenal by Captain John Schofield acting on the authority of President Lincoln.

As the Missouri militiamen were being marched under guard back to the Arsenal near the riverfront, angry crowds confronted the Federal forces, and the confused situation soon devolved into rioting and gunfire.

Over 27 people were killed and the Camp Jackson Affair helped to polarize the state and send Missouri down the road to its own internal civil war.