The Fifth Illinois served at Helena, Arkansas from July, 1862 to their move to Vicksburg in May 1863.  While stationed at the river town, the regiment lost almost a quarter of the men due to unsanitary conditions, which created an environment for such killer diseases as dysentery, typhoid, typhus, and chronic diarrhea.  The state of the medical profession, which was before the advent of modern medicine, also led to overdoses of medicine and treatments that used ingredients that are today classified as poisonous.  "This God Forsaken Town: Death and Disease at Helena, Arkansas, 1862" chronicles the Army of the Southwest and the Fifth Illinois regiment's fight for survival during their first six months at what was considered the most insalubrious posting in American during the Civil War.

The Fifth Illinois moved to Vicksburg, Mississippi when Ulysses S. Grant surrounded the gilbraltar in May 1863.  Grant needed cavalry to protect his lines from attack by Confederate cavalry.  This article chronicles the Fifth Illinois's fight against Confederate General William H. T. Walker's cavalry division at Mechanicsburg, and Capt. Calvin Mann, Company K, and his forty men as they raided southern Mississippi in June 1863.

Back to Helena, Arkansas in October 1862, when a detachment of Fifth Illinois soldiers was commanded by an inexperienced lieutenant during a foraging expedition to the McAlpin plantation.  This was one of the regiment's lowest points during their service when they were ambushed and attacked by Texas cavalry.

With a Confederate invasion threatening Helena, Union troops under the Fifth Kansas's Col. Powell Clayton, led a cavalry force to cut of the rebel army's march south from Missouri.  Clayton's forces met John S. Marmaduke's cavalry at Taylor's Creek and Mount Vernon, Arkansas.  Only through the Confederate's incompetency, did Clayton win the day.