The Colonel of this regiment was Jackson J. Woods, of this county. Most of Company I was composed of Jackson County volunteers. The regiment was organized at Dubuque, and mustered into the service Nov. 25. 1861.

The first battle in which the Twelfth Infantry was engaged was at Fort Donelson, where it was in the front line during the battles of the 13th, 14th and 15th of February, 1862. At the battle of Shiloh, about 400 of the regiment were taken prisoners, and the remainder were organized with the Eighth and Fourteenth Iowa and Fifty-eighth Illinois into the Union Brigade. The brigade took an prominent part in the battle of Corinth.

The prisoners having been exchanged October 18, 1862, the regiment was ordered to Davenport to re-organize. It was next ordered to report to Gen. Grant, and was present at the capture of Jackson, Miss., and the siege of Vicksburg.

December 25, 1863, 29S of the regiment re-enlisted as veterans, and the veterans were furloughed for thirty days, beginning March 22, 1864.  The other important battles in the memory of the Twelfth Iowa are Tupelo, White River, Nashville and Spanish Fort. The regiment was mustered out at Memphis January 20, 1866.

The casualties of enlisted men were 91 killed, 210 died of disease, 247 discharged for disability. Total, 548.