45th Ohio Infantry ​in the American Civil War

Overview

The 45th 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 Chase, Ohio, the regiment mustered in on August 19, 1862, for a three-year term. The unit saw service in the Western Theater, participating in numerous campaigns and engagements across Kentucky, Tennessee, Georgia, and during the pursuit of Confederate cavalry raids into Indiana and Ohio.

The regiment is noted for its rapid deployment to Kentucky immediately after organization, its conversion to mounted infantry in early 1863, and its active role in both field operations and major campaigns, including the Atlanta Campaign and the pursuit of Hood into Tennessee.

Organization & Service

The 45th Ohio Infantry (Three Years’ Service) was organized at Camp Chase, Ohio, and mustered into Federal service on August 19, 1862. The day after mustering, the regiment was ordered to Cynthiana, Kentucky, where it remained until the advance of Confederate General Kirby Smith forced a withdrawal to Covington, Kentucky.

In February 1863, the regiment was mounted at Danville, Kentucky, and began operating as mounted infantry. It engaged in active pursuit of Confederate cavalry between Crab Orchard and Mount Sterling. The regiment saw its first combat at Dutton’s Hill, suffering its first mortal casualty. Subsequent actions at Monticello and Rocky Gap resulted in additional losses, including two killed and several wounded.

The 45th Ohio played a significant role in the pursuit of Confederate forces during Morgan’s Raid, moving from the Cumberland River to the Ohio River at Brandenburg, and then through Indiana and Ohio to Buffington Island, where part of Morgan’s command surrendered. During this pursuit, the regiment, often in the advance, sustained casualties including one mortally wounded and several slightly wounded.

Returning to Tennessee, the regiment was engaged at Philadelphia, suffering three killed, four mortally wounded (including one officer), and over 100 captured. At the Holston River in November 1863, the regiment was attacked and overpowered, resulting in 100 men and officers captured, five killed, and several wounded. During the siege of Knoxville, the regiment lost five killed and six mortally wounded, including the adjutant. The regiment also participated in the action at Bean’s Station without loss.

In May 1864, the 45th Ohio fought at Resaca during the Atlanta Campaign, losing two killed and three mortally wounded. The regiment continued to participate in the Atlanta Campaign and later joined the pursuit of Hood’s forces into Tennessee. The regiment was mustered out of service on June 12, 1865.

Engagements & Campaigns

• Defense of Kentucky (August–September 1862)
• Operations in Kentucky (1862–1863)
• Dutton’s Hill
• Monticello
• Rocky Gap
• Pursuit of Morgan’s Raid (June–July 1863)
• Buffington Island
• Philadelphia, Tennessee
• Holston River
• Siege of Knoxville (November 1863)
• Bean’s Station
• Resaca (May 1864)
• Atlanta Campaign (1864)
• Pursuit of Hood into Tennessee (late 1864)

Casualties

According to available primary sources, the 45th Ohio Infantry (Three Years’ Service) suffered the following losses in key engagements:

• Dutton’s Hill: 1 mortally wounded
• Monticello and Rocky Gap: 2 killed, several wounded (2 mortally)
• Buffington Island: 1 mortally wounded, a few slightly wounded
• Philadelphia, Tennessee: 3 killed, 4 mortally wounded (including 1 officer), over 100 captured
• Holston River: 5 killed, several wounded, 100 captured
• Siege of Knoxville: 5 killed, 6 mortally wounded (including adjutant)
• Resaca: 2 killed, 3 mortally wounded

Total regimental losses for the full term are not specified in the cited sources. Some details are incomplete in surviving primary sources.

Field Officers & Commanders

• Colonel Benjamin P. Runkle
• Lieutenant Colonel Alexander S. Ramsey
• Lieutenant Colonel Joseph Hill
• Lieutenant Colonel George E. Ross
• Lieutenant Colonel John H. Humphrey
• Major James E. Marsh
• Major James T. Jennings

Regimental Roster

The full roster of the 45th 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 as recorded in official state and federal records.

To view the complete roster, visit the 45th Ohio Infantry (Three Years’ Service) Roster page.

Sources & References

• Official Records of the Union and Confederate Armies, Series I, various volumes and parts (see reports on Kentucky and Tennessee operations, Morgan’s Raid, and the Atlanta Campaign)
• Ohio Roster Commission, “Official Roster of the Soldiers of the State of Ohio in the War of the Rebellion,” Vol. 5
• 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