The 166th Ohio Infantry Regiment lost 39 enlisted men to disease during the Civil War.

1864
Organized at Camp Cleveland, Ohio
May 13 960 men were mustered in under Colonel Harrison G. Blake
May 15 Left State for Washington, D.C. Attached to 2nd Brigade, DeRussy’s Division, 22nd Army Corps.
July Assigned to duty as garrison at Forts Richardson, Barnard, Reynolds, Ward and Worth (Headquarters at Fort Richardson), Defenses of Washington south of the Potomac. Attached to 3rd Brigade, DeRussy’s Division, 22nd Army Corps.
July 11-12 Repulse of Early’s attack on Washington
September 9 Mustered out