Organized at St. Louis, Mo., May 7, 1861. Attached to Lyon's Army of the West. Capture of Camp Jackson, St. Louis, May 10. Duty at St. Louis until July 23 (Co. "A" detached guarding bridge on Northern Missouri Railroad June 16-August 14.) A Detachment moved to Bird's Point, Mo., July 23, and duty there until August 14. Moved to St. Louis. A Detachment guard bridges on St. Louis & Iron Mountain Railroad. Mustered out August 16, 1861.