|127th Regiment Illinois Volunteer Infantry|
|Active||September 6, 1862 - June 17, 1865|
|Allegiance||United States Army Union Army|
|Engagements||American Civil War
Yazoo Pass Expion|
Battle of Chickasaw Bayou
Battle of Arkansas Post
Battle of Champion Hill
Siege of Vicksburg, May 19 & May 22 assaults
Battle of Missionary Ridge
Battle of Resaca
Battle of Dallas
Battle of New Hope Church
Battle of Allatoona
Battle of Kennesaw Mountain
Battle of Atlanta
Siege of Atlanta
Battle of Jonesboro
Battle of Lovejoy's Station
Sherman's March to the Sea
Battle of Bentonville
The regiment was attached to 4th Brigade, 5th Division, District of Memphis, XIII Corps, Department of the Tennessee, November 1862. 2nd Brigade, 2nd Division, XIII Corps, to December 1862. 2nd Brigade, 2nd Division, Sherman's Yazoo Expion, to January 1863. 2nd Brigade, 2nd Division, XV Corps, Army of the Tennessee, to September 1863. 1st Brigade, 2nd Division, XV Corps, to June 1865.
The 127th Illinois Infantry mustered out of service June 4, 1865, and was discharged at Chicago on June 17, 1865.
Moved to Memphis, Tennessee, November 9–13, 1862. Duty at Camp Douglas, Illinois, guarding prisoners, September 6 to November 9, 1862. Grant's Mississippi Central Campaign. "Tallahatchie March" November 26-December 13. Sherman's Yazoo Expion December 20, 1862 to January 3, 1863. Chickasaw Bayou December 26–28, 1862. Chickasaw Bluff December 29. McClernand's Expion to Arkansas Post, Arkansas, January 3–10, 1863. Assault and capture of Fort Hindman, Arkansas Post, January 10–11. Moved to Young's Point, Louisiana, January 22, and duty there until March. Expion to Rolling Fork, via Muddy. Steele's and Black Bayous and Deer Creek March 14–27. Deer Creek March 22. Demonstrations on Haines' and Drumgould's Bluffs April 29-May 2. Movement to Jackson, Mississippi, via Grand Gulf, May 2–14. Jackson May 14, Champion Hill May 16. Siege of Vicksburg, Mississippi, May 18-July 4. Assaults on Vicksburg May 19 and 22. Surrender of Vicksburg July 4. Advance on Jackson, Mississippi, July 4–10. Siege of Jackson July 10–17. At Big Black until September 22. Moved to Memphis, Tennessee; then marched to Chattanooga, Tennessee, September 22-November 20. Operations on Memphis & Charleston Railroad in Alabama October 20–29. Bear Creek, Tuscumbia, Alabama, October 27. Chattanooga-Ringgold Campaign November 23–27. Foot of Missionary Ridge November 24. Tunnel Hill November 24–25. Missionary Ridge November 26. Pursuit to Graysville November 26–27. March to relief of Knoxville November 28-December 8. At Larkinsville, Alabama, until May 1864. Atlanta Campaign May to September. Demonstration on Resaca May 8–13. Battle of Resaca May 14–15. Movement on Dallas May 18–25. Operations on line of Pumpkin Vine Creek and battles about Dallas, New Hope Church, and Allatoona Hills May 25-June 5. Operations about Marietta and against Kennesaw Mountain June 10-July 2. Assault on Kennesaw June 27. Nickajack Creek July 2–5. Chattahoochie River July 6–17. Battle of Atlanta July 22. Siege of Atlanta July 22-August 25. Ezra Chapel, Hood's second sortie, July 28. Flank movement on Jonesboro August 25–30. Battle of Jonesboro August 31-September 1. Lovejoy's Station September 2–6. Operations against Hood in northern Georgia and northern Alabama September 29-November 3. March to the Sea November 15-December 10. Clinton November 23. Siege of Savannah December 10–21. Assault and capture of Fort McAllister December 13. Campaign of the Carolinas January to April 1865. Salkehatchie Swamps, South Carolina, February 2–5. South Edisto River February 9. North Edisto River February 12–13. Columbia February 16–17. Battle of Bentonville, North Carolina, March 20–21. Occupation of Goldsboro March 24. Advance on Raleigh April 10–14. Occupation of Raleigh April 14. Bennett's House April 26. Surrender of Johnston and his army. March to Washington, D.C., via Richmond, Virginia, April 29-May 19. Grand Review of the Armies May 24.
The regiment lost a total of 218 men during service; 2 officers and 47 enlisted men killed or mortally wounded, 1 officer and 168 enlisted men died of disease.