Of the one-hundred and forty-eight citizens of Mansfield who served during the Civil War, forty-one of them saw action with the 21st. The 21st volunteer infantry was commissioned on September 5th, 1862 with a complement of 965 recruits, a number that would later swell to 1,023. After brief and uneventful tours with the 9th Corps, and the 7th Corps, the 21st regiment first saw significant action with the 18th Corps.
On May 16th, 1864 the 21st Regiment occupied the right side of the Union line during the Battle of Drewry’s Bluff. Several hours of hard fighting ensued when Confederate forces attacked under the cover of heavy fog in an effort to capture a railroad line linking Richmond and Petersburg. Unable to hold against the Confederate advance, the 21st Regiment and other elements of the 1st Division were forced to retreat and relinquish the railroad to the Confederate forces. The 21st regiment sustained its heaviest losses of the war during this battle with 79 wounded, 23 captured, and 16 killed including one Mansfield citizen.
Following the retreat from Drewry’s Bluff, the 21st traveled to White House Landing where it would support the Army of the Potomac in several engagements near Cold Harbor beginning on May 29th and running through June 9th. After the evacuation of Cold Harbor, a large Union force including the 21st regiment advanced on Petersburg. After supporting an initial charge against the Confederate lines on June 17th, the 21st regiment was relegated to a reserve role, and performed picket and skirmish duties for the next 3 weeks. During this time a total of 49 casualties were incurred.
The battle at Petersburg proved to be the final major engagement for the 21st Infantry Regiment during the war. After Petersburg, the regiment participated in a raid on Fredricksburg on March 4th 1865 intended to curb the trade of tobacco for supplies by the Confederate Army. The 21st was among the first infantry troops to enter Richmond on April 3, 1865.
The service of the 21st Connecticut Volunteer Infantry in the Union Army was officially ended on June 16th 1865. A week later the regiment arrived home in New Haven before later attending a celebration at the State House in Hartford. All members of the 21st regiment were finally discharged and the regiment formally was disbanded on July 6th 1865.