This is a remnant of the 3rd Regiment U. S. Reserve Corps flag, a unit organized in St. Louis, Missouri in May 1861, with Colonel John McNeil as commander. The regiment took part in the capture of Camp Jackson in St. Louis, and in an expedition into Callaway County, Missouri, where it defeated Secessionist troops and took possession of the city of Fulton. The regiment returned to St. Louis after three months of service and was mustered out. Most of the troops reentered service in the 4th Missouri Volunteer Infantry.
Image Courtesy Wilson’s Creek National Battlefield; WICR 30022