The 18th Regiment Illinois Volunteer Infantry was an infantry regiment that served in the Union Army during the American Civil War.
Service
Organized at Aurora, Ill., and mustered into State service May 19, and into U. S. service May 28, 1861. Moved to Bird's Point, Mo., June 24, and duty there till August 26. Moved to Mound City August 26, and duty there till October 5. Moved to Cairo, Ill., October 5, and duty there till February, 1862. Attached to District of Cairo, to October, 1861. 1st Brigade, District of Cairo, to February, 1862. 1st Brigade, 1st Division, District of Cairo, February, 1862. 2nd Brigade, 1st Division, District of West Tenn., March, 1862. 1st Brigade, 1st Division, 1st District, West Tenn., and Army of the Tennessee, to July, 1862. 1st Brigade, 1st Division, District of Jackson, Tenn., to September, 1862. 2nd Brigade, 1st Division, District of Jackson, to November, 1862. District of Jackson, 13th Army Corps (Old), Dept. of the Tennessee, to December, 1862. 1st Brigade, District of Jackson, 16th Army Corps, to March, 1868. 2nd Brigade, 3rd Division, 16th Army Corps, to May, 1863. 2nd Brigade, Kimball's Provisional Division, 16th Army Corps, to July, 1863. 2nd Brigade, Kimball's Provisional Division, District of Eastern Ark., to August, 1863. 1st Brigade, 2nd Division, Arkansas Expedition, to November, 1863. 3rd Brigade, 2nd Division, Arkansas Expedition, to January, 1864. 3rd Brigade, 2nd Division, 7th Army Corps, Dept. of Arkansas, to April, 1864. Post Pine Bluff, Ark., 7th Army Corps, to May, 1864. 1st Brigade, 2nd Division, 7th Army Corps, to January, 1865. Pontoneers, 7th Army Corps, to May, 1865. 1st Brigade, 1st Division, 7th Army Corps, to August, 1865. Dept. of Arkansas, to December, 1865.