100th Ohio Infantry ​in the American Civil War

Overview

The 100th Ohio Infantry (Three Years’ Service) was an infantry regiment from Ohio that served in the Union Army during the American Civil War. Organized at Camp Toledo between July and September 1862, the regiment was mustered in for three years of service. The unit participated in several major campaigns in the Western Theater, including the defense of Cincinnati, the East Tennessee operations, the Atlanta Campaign, and the Nashville Campaign. The regiment is noted for its heavy losses during the assault on Atlanta and for the significant number of men captured and lost in Confederate prisons.

Organization & Service

The 100th Ohio Infantry (Three Years’ Service) was organized at Camp Toledo, Ohio, in July, August, and September 1862. Upon completion of organization, the regiment was ordered to Cincinnati to assist in the defense of the city, taking up positions on Covington Heights near Fort Mitchel. The regiment remained in Kentucky for nearly a year, moving as needed in response to Confederate threats.

In late 1863, the regiment was sent to East Tennessee, where it participated in the defense of Knoxville. In the spring of 1864, the 100th Ohio joined the Atlanta Campaign, being engaged in nearly every major battle from Rocky Face Ridge to Atlanta. On August 6, 1864, the regiment suffered severe losses during an assault on Confederate works in front of Atlanta, losing 103 men out of 300 engaged. Following the fall of Atlanta, the regiment participated in the pursuit of Hood’s army and fought at the battles of Franklin and Nashville. In early 1865, the regiment moved to North Carolina, where it continued to serve until the end of the war. The 100th Ohio Infantry was mustered out of service on June 20, 1865.

Engagements & Campaigns

• Defense of Cincinnati (September 1862)
• Operations in Kentucky (1862–1863)
• East Tennessee Campaign, including the defense of Knoxville (late 1863)
• Atlanta Campaign (May–September 1864), including Rocky Face Ridge, Resaca, Dallas, Kennesaw Mountain, and the assault on Atlanta (August 6, 1864)
• Pursuit of Hood after the fall of Atlanta (autumn 1864)
• Battle of Franklin (November 30, 1864)
• Battle of Nashville (December 15–16, 1864)
• Operations in North Carolina (early 1865)

Casualties

• Killed in action: 65
• Died of wounds: 27
• Died of disease: 108
• Wounded: 142
• Captured by the enemy: 325 (of whom 85 died in Confederate prisons)

Some details are incomplete in surviving primary sources.

Field Officers & Commanders

• Colonel John C. Groom
• Colonel Patrick S. Slevin
• Colonel Edwin S. Hayes
• Lieutenant Colonel Frank Rundell
• Major John A. Shannon

Regimental Roster

The full roster of the 100th Ohio Infantry (Three Years’ Service), including officers and enlisted men, is available for genealogical and historical research. This roster provides names, ranks, and service details for members of the regiment.

To view the complete roster, visit the 100th Ohio Infantry (Three Years’ Service) Roster page.

Sources & References

• Official Records of the Union and Confederate Armies, Series I, Vol. 16, 23, 38, 45
• Ohio Adjutant General’s Report
• Dyer, Frederick H., A Compendium of the War of the Rebellion
• Fox, William F., Regimental Losses in the American Civil War
• The Union Army, Federal Publishing Company, 1908, Vol. 2