After Pea Ridge, Van Dorn transferred his army to Corinth, Mississippi. The Corinth camps were unhealthy and 43 men from the 3rd Texas Cavalry died of sickness. During the 20 May 1862 reorganization, 200 more soldiers were discharged because they were too young, too old, or physically unfit. The regiment helped cover the 29–30 May evacuation after the Siege of Corinth ended. On 19 September 1862, the regiment suffered its worst losses of the war in the Battle of Iuka, with 22 killed, 74 wounded, and 48 captured. During the battle, the 3rd Texas Cavalry was assigned to Hebert's brigade in Lewis Henry Little's division. A few weeks earlier, the 3rd Texas Cavalry sent their horses to graze so they fought the battle on foot. Hebert ordered the regiment to form a skirmish line and advance into a ravine in front of the Union positions. As Colonel Hinchie P. Mabry led the 3rd Texas Cavalry forward, Union riflemen and artillery opened fire at a range of . Sergeant W. P. Helm watched as a round shot beheaded his company commander, while canister shot chopped a lieutenant and a private in half. Soon Hebert's brigade attempted to seize the 11th Ohio Battery, which became the focus of the fighting. Part of the 3rd Texas Cavalry helped the 1st Texas Legion rout the 48th Indiana Infantry Regiment and reach the top of the ridge. Sam Barron saw four men killed near him while Sergeant Helm claimed that 27 of 42 men from his company were casualties. The 3rd Texas Cavalry lost some men to friendly fire when the 1st Texas Legion mistakenly shot at them. After a terrific struggle, the 3rd Texas Cavalry and other units captured the Ohio battery. Barron remarked of the Federal gunners, "the brave defenders standing nobly to their posts until they were nearly all shot down." Colonel Mabry was wounded in the ankle.