Many members of the 1st Maine Volunteer Infantry reenlisted as members of the 10th Maine Volunteer Infantry Regiment when it was formed in October 1861. It fought at the battles of Cedar Mountain and Antietam in 1862. Most enlistments in the 10th Maine expired on 8 May 1863 except for 3 companies of "three year men" who were retained in service as the 10th Maine Battalion. The 10th Maine Battalion served as the Provost Guard for the Army of the Potomac at the Battle of Gettysburg. The 29th Maine Volunteer Infantry Regiment was mustered into service on December 17, 1863, and was transferred to the southern theater, fighting in Louisiana in the Red River Campaign from March to May 1864, and then in Virginia from July 1864 to April 1865. On 29 May 1864, the 10th Maine Battalion was consolidated with the 29th Maine, thus establishing continuity with the 10th Maine Regiment and the 1st Maine Regiment. The 29th Maine served on occupation duty in South Carolina starting in June 1865 and was mustered out of service on June 21, 1866.