The regiment was immediately ordered with the remainder of Rust's Brigade to Fort Pillow, approximately 50 miles north of Memphis.

[7] All twelve-month regiments had to re-muster and enlist for two additional years or the duration of the war; a new election of officers was ordered; and men who were exempted from service by age or other reasons under the Conscription Act were allowed to take a discharge and go home.

Part of Green's brigade, including many from the 20th Arkansas was captured and Major Robertson was killed in the Battle of Big Black in rear of Vicksburg on May 17, 1863.

[12] The remnants of the regiment fell back inside the works and endured the forty plus day Siege of Vicksburg.

[13] General U. S. Grant initially demanded the conditional[verification needed] surrender of the Vicksburg garrison, but faced with the necessity of feeding 30,000 starving Confederates and having the idea that these soldiers might do more harm to the Confederate cause by being released to return home rather than being exchanged as whole units, he relented and allowed for the immediate parole of the unit.

The able bodied Confederate soldiers who were released on parole walked out of Vicksburg (they were not allowed to proceed in any military formations) on July 11, 1863.

Most of the Arkansas units appeared to have bypassed the established parole camps, and possibly with the support, or at least by the compliancy, of their Union captors, simply crossed the river and returned home.

Because so many of the Vicksburg parolees, especially from Arkansas, simply went home, Major General Pemberton requested Confederate President Davis grant the men a thirty- to sixty-day furlough.

[15] The furloughs were not strictly adhered to so long as the soldier eventually showed up at a parole camp to be declared exchanged and returned to duty.

[16] Eventually exchanged, reorganized, and mounted, at Washington, Arkansas, in the fall of 1863, the 20th was attached to Dockery's Brigade in the Trans-Mississippi Department.

After being exchanged, the regiment re-entered the service as cavalry under Colonel Jones, and during the Camden Expedition[18] in March and April 1864, was at the skirmishes on the Little Missouri and Prairie d'Ane,[19] and the battles of Marks' Mills[20] and Jenkins' Ferry[21] in April 1864; and during Price's Missouri Raid river took part in the battles of Pilot Knob, Booneville, Independence and Marais des Cygnes, September and October 1864.