3rd Missouri Volunteer Infantry (3 months, 1861)

The 3rd Missouri Volunteers 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 Third 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.

Upon entry into Federal service the members of the new Third Missouri elected Franz Sigel colonel of the regiment. The new Missouri Volunteer regiments, subsequently elected (then) Captain Nathaniel Lyon as the brigadier general of the new brigade of Missouri volunteers. President Lincoln would later confirm Lyon's promotion from Captain to Brigadier general.

The regiment, composed almost completely of ethnic Germans, was unusually large, with ten infantry companies and two rifle companies.

Military Service
On May 10, 1861 the Third Missouri under Colonel Blair participated in the arrest of the Missouri Volunteer Militia drilling at Camp Jackson at Lindell Grove on the western border of St. Louis City. As the Missouri militiamen were being march 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.

After June 12, 1861 the Third Missouri was part of a complex movement against the Missouri State Guard. On force, under Brigadier General Lyon moved up the Missouri River by steamer, to capture the State capital at Jefferson City. A second brigade, composed of the 3rd and 5th Missouri and two batteries of artillery moved into southwest Missouri under the overall command of Colonel Sigel, to cut off any Missouri State Guard troops which might move south before Lyon's advance.

Colonel Sigel took his force to Rolla, thence to Springfield, Missouri arriving on June 25th. They marched to Neosho (June 26-30) and were forced to retreat to Mt. Vernon in the face of a large force of State Guardsmen. Two companies of the Third Missouri who formed Sigel's rear guard were captured covering the retreat.

On July 5, Sigel's force of 1,100 met 4,000 State Guardsmen (and 2,000 unarmed Guard recruits) at the Battle of Carthage. Confronted with the large force of Guardsmen Sigel retreated in good order into Carthage and successfully disengaged and retreated back to Sarcoxie that night.

The Third joined with General Lyon's force at Springfield, and participated in the August 10 Battle of Wilson's Creek. The Third was again part of a brigade (with the Fifth Missouri) under Colonel Sigel. Sigel's 2nd Brigade initially had significant success, attacking Confederate cavalry on the southeast corner of the southern camps (at the Sharp Farm). After driving off these southern troops, Sigel halted his brigade across the Wire Road, above Skeeg's Branch (Creek). However, Sigel positioned his artillery badly (behind the military crest of the ridge) and cautioned his men against accidentally firing on Federal troops he expected to be advancing south down the Wire Road (the 1st Iowa Infantry was uniformed in grey). At this point, Confederate Brigadier Ben McCulloch lead an attack south down the Wire Road, with the respected Third Louisiana Infantry in fore. Skirmishers, officers, and Sigel himself mistook the Louisiana troops for the Iowa infantry allowing them to advance to point blank range before delivering a devastating volley into the confused Federal troops. Sigel shouted "they make a mistake" as his brigade was overrun.

The majority of the shattered Third Missouri escaped, and eventually rejoined the Federal force retreating to Springfield, and then back to Rolla. From there the regiment was ordered back to St. Louis to be demobilized.

The all companies of the regiment were mustered out by September 4, 1861. Elements of the 3rd Missouri Volunteers (3 Months Service) were incorporated in the new 3rd Missouri Volunteer Infantry (3 Years Service) under Colonel Isaac F. Shephard.