The 4th Military District is comprised of:

• 4th Military District Headquarters Company
• Co. C, 34th Illinois Volunteer Infantry Regiment
• Co. A, 3rd Battery Iowa Light Artillery
• Co. B, 10th Iowa Volunteer Infantry
• Co. B, 20th Iowa Volunteer Infantry
• Co. A, 37th Iowa Volunteer Infantry
• Co. M, 1st Missouri Light Artillery
• Co. A, 2nd Missouri Infantry
• Co. C, 5th Missouri Cavalry
• Nebraska Rangers
• Co. B, 28th Wisconsin Volunteer Infantry
• Cushing's Battery (Battery A, 4th U.S. LA)
• Mulligan's Battery (Battery L, 1st Illinois LA)