The 18th Arkansas Infantry Regiment or Carroll's Arkansas Infantry Regiment was an infantry formation in the Confederate States Army during the American Civil War. The regiment was raised in April 1862 under the command of Col. D Carroll. It served east of the Mississippi in several actions before being surrendered at Port Hudson in July 1863. Re-organized, the regiment was finally merged with several other Arkansas units to form the 2nd Arkansas Consolidated Infantry Regiment. There was another regiment designated as the 18th Arkansas. When Lieutenant-Colonel John Sappington Marmaduke's 1st Arkansas Infantry Battalion was increased to a regiment, it was briefly designated as the 18th (Marmaduke's) Arkansas Infantry Regiment. Marmaduke's regiment was subsequently redesignated as the 3rd Confederate Infantry Regiment.