Organized at Camp Douglas, Chicago, Ill., February 11, 1862. Moved to Cairo, Ill., thence to Fort Donelson, Tenn., February 11-13. Attached to 2nd Brigade, 3rd Division, District of Cairo, February, 1862. 3rd Brigade, 2nd Division, District of West Tennessee, and Army of the Tennessee, to May, 1862. 1st Brigade, 2nd Division, Army of the Tennessee, to July, 1862 (Detachment). 1st Brigade, 2nd Division, District of Corinth, Miss., to November, 1862. 1st Brigade, 2nd Division, District of Corinth, 13th Army Corps (Old), Department of the Tennessee, to December, 1862. Springfield, Ill., to June, 1863. District of Columbus, Ky., 6th Division, 16th Army Corps, Dept. of the Tennessee, to January, 1864. 1st Brigade, 3rd Division, 16th Army Corps, Army of the Tennessee, to March, 1864, and Dept. of the Gulf to June, 1864. 1st Brigade, 3rd Division, 16th Army Corps, Dept. of the Tennessee, to November, 1864. 2nd Brigade, 2nd Division, 16th Army Corps, to December, 1864. 2nd Brigade, 2nd Division (Detachment), Army of the Tennessee, Department of the Cumberland, to February, 1865. 2nd Brigade, 2nd Division, 16th Army Corps (New), Military Division of West Mississippi, to March, 1865. 3rd Brigade, 2nd Division, 16th Army Corps, to August, 1865. District of Alabama to April, 1866.

SERVICE - Investment and capture of Fort Donelson, Tenn., February 14-16. Occupation of Fort Henry February 18 - March 6. Moved to Savannah, thence to Pittsburg Landing, Tenn., March 6-25. Battle of Shiloh, Tenn., April 6-7. Mostly captured. Regiment consolidated into four Companies and organized with remnants of the 2nd, 7th, 12th and 14th Iowa Infantry into a body known as the Union Brigade, Army of the Tennessee. Advance on and siege of Corinth, Miss., April 29 - May 30. Pursuit to Booneville May 31 - June 6. Duty at Corinth till October. March to Iuka September 18-20. Battle of Corinth, Miss., October 3-4. Pursuit to Ruckersville October 5-12. The several detachments of Regiment concentrated at Camp Butler, Ill., in December, 1862, and on duty guarding prisoners till June, 1863. Ordered to Cairo, Ill. Garrison duty at Cairo and Mound City, Ill., Paducah and Mayfield, Ky., till January, 1864. Action at Mayfield November 2, 1863. Skirmish Obion River, near Union City, Tenn., November 19, 1863 (Cos. "G," "H," "I," "K"). Ordered to Vicksburg, Miss., January 21. Meridian Campaign February 3 - March 2. Red River Campaign March 10 - May 12. Fort DeRussy March 14. Occupation of Alexandria March 16. Battle of Pleasant Hill April 9. Natchitoches April 20-21. About Cloutiersville April 22-24. At Alexandria April 26 - May 13. Retreat to Morganza May 13-20. Mansura May 16. Yellow Bayou May 18. Moved to Vicksburg, Miss.; thence to Memphis, Tenn., May 22 - June 10. Lake Chicot, Ark., June 6. Defeat of Marmaduke. Smith's Expedition to Tupelo, Miss., July 5-21. Near Camargo's Cross Roads July 13. Harrisburg, near Tupelo, July 14-15. Old Town (or Tishamingo Creek), July 15. Smith's Expedition to Oxford, Miss., August 1-31, Tallahatchie River August 7-9. Abbeville August 23. Mower's Expedition to Brownsville, Ark., September 2-10. March through Arkansas and Missouri in pursuit of Price September 17 - November 19. Moved to Nashville, Tenn., November 21 - December 1. Battle of Nashville December 15-16. Pursuit of Hood to the Tennessee River December 17-28. Moved to Eastport, Miss., and duty there till February, 1865. Expedition from Eastport to Iuka January 9, 1865. Movement to New Orleans, La., February 8-26; thence to Dauphin Island, Ala., March 6. Campaign against Mobile and its defenses March 17 - April 12. Siege of Spanish Fort and Fort Blakely March 26 - April 8. Assault and capture of Fort Blakely April 9. Occupation of Mobile April 12. March to Montgomery April 13-25. Duty at Montgomery and in the District of Alabama till April, 1866.

Mustered out April 15, 1866.

Regiment lost during service 8 Officers and 75 Enlisted men killed and mortally wounded and 4 Officers and 211 Enlisted men by disease. Total 298.