On May 10, 1861, the Third U.S.R.C under Colonel McNeil participated in the arrest of the
Missouri Volunteer Militia drilling at Camp Jackson at Lindell Grove on the western border of St. Louis City, who were suspected of being involved in a Confederate plot to seize the
federal arsenal in St. Louis. 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. The 3rd U.S.R.C. served as part of the St. Louis garrison until July 1, 1861, when three of its companies joined Brigadier General Lyon's Southwest Expedition. On July 16, six additional companies marched on
Callaway County, Missouri, where after a skirmish with members of the secessionist
Missouri State Guard, they occupied
Fulton. The regiment returned to St. Louis, where in September part of the unit's manpower was mustered out of service at the expiration of their enlistment. The regiment was reorganized under the command of Colonel Charles A. Fritz, who had been the regiment's lieutenant colonel, with a mixture of those who chose to reenlist and new recruits. In January 1862, the 3rd U.S.R.C Infantry was consolidated with the Gasconade Battalion to form the
4th Missouri Volunteer Infantry Adolphus Busch served as a Corporal in the regiment from May to August, 1861. ==See also==