The 12th Maryland Volunteer Infantry Regiment lost 2 men to disease during the Civil War.
|July 30||Organized at Baltimore, Maryland, for 100 days and attached to the 1st Separate Brigade, 8th Army Corps|
|On guard duty along the Baltimore & Ohio Railroad between Baltimore, Md., and Kearneysville, Va.|
|September||Assigned to Reserve Division West Virginia|
|November 14||Mustered out|