The Clark Township Southern Guards was a cavalry company organized in Cole County on 6 February 1861, under the command of Capt. Fountain M. McKenzie, a veteran of the War with Mexico. When troops gathered at Jefferson City in the immediate aftermath of the "Camp Jackson Massacre", the company was present and was incorporated into a cavalry squadron with a company from Miller County lead by Capt. James Johnson. This would have been shortly after May 10.

The 1st Cavalry Regiment, Sixth Division, Missouri State Guard, was organized at Camp Briscoe, St. Clair County, on 26 June 1861, under commaqnd of Col. William B. Brown of Saline County. The Clark Township Southern Guards constituted Company B (or maybe A, depending on the source) of the regiment. At muster-in, the company counted 82 men on its roll.

The 1st Cavalry fought at Carthage, Wilson's Creek, Second Boonville, and Lexington. Part of the regiment apparently also participated in the battle at Elkhorn Tavern (Pea Ridge, Ark.) in March, 1862, but its make-up at that time is unknown.

Capt. McKenzie was killed at Carthage on 5 July 1861. After the death of McKenzie, 1st Lt. B. S. Bond was promoted to captain and company commander. Bond, however, "abandoned" the company on 12 August, two days after the battle of Wilson's Creek, as did 1st Lt. J. H. Bond. Command of the company then appears to have fallen on 2nd Lt. Nelson Martin.

It is not know just when the 1st Cavalry Regiment disbanded, but many units left the service in late 1861. It is almost a certainty that the 1st Cavalry Regiment as originally constituted did not engage at Elkhorn Tavern.