3rd Regiment, US Reserve Corps, Missouri Infantry (Union)

Organized at St. Louis. Mo., August and September, 1861. Attached to 2nd Brigade, Sigel's Division, Fremont's Army of the West. Fremont's Campaign in Missouri September to November. At Rolls, Mo., till January, 1862. Consolidated with Gasconade Battalion to form 4th Missouri Infantry January 18, 1862.