As part of the Army of Northern Virginia, the 12th Mississippi fought in many battles of the Eastern theater of the American Civil War before surrendering in April 1865.

[1] After the retreat from Pennsylvania, the regiment fought at Bristoe Station, where brigade commander Carnot Posey was killed, and Mine Run before spending the winter in Virginia.

This location was the site of some of the fiercest combat of the civil war, as Union and Confederate troops made desperate attacks and counter-attacks over nearly 24 hours of continuous battle.

During the final stages of the Siege of Petersburg, the 12th was assigned to hold Fort Gregg, and took part in brutal hand-to-hand fighting during the Federal breakthrough on April 2.

The survivors were captured, although at least some men of the 12th escaped the fall of Petersburg and were present at the final surrender of the Army of Northern Virginia at Appomattox Court House on April 9, 1865.