Overview
The 100th Indiana Infantry (Three Years’ Service) was an infantry regiment from Indiana that served in the Union Army during the American Civil War. Organized at Fort Wayne in August 1862, the regiment was mustered into Federal service on September 10, 1862. It served primarily in the Western Theater and participated in several major campaigns and battles with the Army of the Tennessee and the 15th Army Corps.
The regiment was notable for its involvement in the Vicksburg and Atlanta campaigns, as well as the March to the Sea and the Carolinas Campaign. The 100th Indiana Infantry mustered out of service on June 9, 1865, in Washington, D.C.
Organization & Service
The 100th Indiana Infantry was organized at Fort Wayne, Indiana, in August 1862. Two companies originally intended for the 98th Indiana Infantry were assigned to the 100th to complete its organization. The regiment was mustered into service on September 10, 1862, with an original strength of 968 men.
On November 1, 1862, the regiment departed Indiana for Memphis, Tennessee, where it was assigned to the 2nd Brigade, 1st Division, Army of the Tennessee. It participated in the initial expedition against Vicksburg but was forced to return due to the Confederate capture of Holly Springs. The regiment then performed garrison and railroad guard duty at Collierville, Tennessee.
In June 1863, the 100th Indiana joined the army at Vicksburg and took part in the siege. After the fall of Vicksburg, it was engaged at Jackson, Mississippi, remaining in action until the city’s evacuation. The regiment camped at Big Black River until late September, then moved to Memphis and subsequently to Stevenson and Bridgeport, Alabama, and Trenton, Georgia.
The regiment participated in the movement that turned the left flank of Bragg’s army and fought at Lookout Mountain. It arrived at Chattanooga in time to take part in the storming of Missionary Ridge, where its division gained and held the crest against repeated assaults, suffering 132 killed and wounded. After pursuing the enemy to Graysville, the regiment was ordered to Knoxville for the relief of Burnside, then moved to Scottsboro, Alabama, arriving December 26, 1863.
On May 1, 1864, the 100th Indiana joined the Atlanta Campaign, engaging at Dalton, Snake Creek Gap, Resaca, Dallas, New Hope Church, Big Shanty, Kennesaw Mountain, Nickajack Creek, Cedar Bluffs, Chattahoochee River, Decatur, Jonesboro, and Lovejoy’s Station. Following the evacuation of Atlanta, the regiment encamped at East Point before pursuing Hood’s forces in October as far as the Tennessee River, then returned to Atlanta.
As part of the 2nd Brigade, 1st Division, 15th Army Corps, the regiment participated in the March to the Sea, fighting at Griswoldville, Georgia. After reaching Savannah, it moved by steamer to Beaufort, South Carolina, and advanced through the Carolinas, assisting in the capture of Branchville, Columbia, Georgetown, and Cheraw, South Carolina, and fighting at Bentonville, North Carolina. The regiment was at Goldsboro from March 26 to April 10, then moved to Raleigh, Richmond, and finally Washington, D.C., where it was mustered out on June 9, 1865. Remaining recruits were transferred to the 48th Indiana Infantry.
Research This Regiment Further
If you’d like to explore this unit’s history in more depth, regimental histories and Civil War reference works offer valuable detail.
Engagements & Campaigns
- Expedition against Vicksburg (1862)
- Garrison and railroad guard duty at Collierville, Tennessee
- Siege of Vicksburg (June–July 1863)
- Operations against Jackson, Mississippi (July 1863)
- Lookout Mountain (November 1863)
- Missionary Ridge (November 1863)
- Pursuit to Graysville
- Relief of Knoxville
- Atlanta Campaign (May–September 1864): Dalton, Snake Creek Gap, Resaca, Dallas, New Hope Church, Big Shanty, Kennesaw Mountain, Nickajack Creek, Cedar Bluffs, Chattahoochee River, Decatur, Jonesboro, Lovejoy’s Station
- Pursuit of Hood (October 1864)
- March to the Sea (November–December 1864): Griswoldville
- Carolinas Campaign (1865): Branchville, Columbia, Georgetown, Cheraw, Bentonville
Casualties
- Original strength: 968
- Gained by recruits: 86
- Total served: 1,054
- Loss by death: 237
- Deserted: 31
- Unaccounted for: 11
Some details are incomplete in surviving primary sources regarding the breakdown of casualties by cause.
Field Officers & Commanders
- Colonel Charles Case
- Colonel Sanford I. Stoughton
- Colonel Albert Heath
- Colonel Ruel M. Johnson
- Lieutenant Colonel Albert Heath
- Lieutenant Colonel Ruel M. Johnson
- Lieutenant Colonel John W. Headington
- Major Robert Parrott
- Major Ruel M. Johnson
- Major John W. Headington
- Major William H. Vernamon
Regimental Roster
The full roster of the 100th Indiana Infantry (Three Years’ Service), including officers and enlisted men, is available for genealogical and historical research. The roster provides details on service records, ranks, and other pertinent information.
To view the complete roster, visit the 100th Indiana Infantry (Three Years’ Service) Roster page.
Sources & References
- Official Records of the Union and Confederate Armies, Series I, Volumes XVII, XXIV, XXXII, XXXVIII, XLIV
- Indiana 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, Volume 3