The Aransas Pass is the navigable waterway between the barrier islands of San José and Mustang which lie on the Coastal Bend of Texas. After the start of the Civil War, this pass became a strategic place. Through it sailed vessels carrying Southern cotton to be exchanged for military supplies from European sources. For this reason the Federals clamped a blockade on the Aransas Pass in early February 1862.
At that time the Confederates had poorly defended this waterway against such action, and, under the command of naval Lt. John W. Kittredge, the Federals freely interdicted Southern shipping and degraded livestock resources on Mustang and San José islands. Lieutenant Kittredge was an effective commander; his operations on the islands and inland waters hampered the war effort in South Texas.
The "Kittredge era" abruptly ended on September 14, 1862, when this officer and a land party of his sailors were surprised and captured by Confederate cavalry near Corpus Christi. Subsequent Federal activity at and around the Aransas Pass was commanded by Lt. Frederic Hill, who proved far less skillful than Kittredge. (Indeed, Confederate actions caused Hill's battered naval command to be withdrawn altogether from its operational area in May 1863.) This weaker Federal presence gave the Confederates the opportunity to fortify the Aransas Pass.
By April 1863 an artillery emplacement had been established on north Mustang Island contiguous to the Aransas Pass. This site was named Fort (aka Camp) Semmes, after Raphael Semmes, a notable Confederate Navy captain. Fort Semmes was manned by personnel of the Eighth Texas Infantry Regiment in a unit known as Neal's Battery under the command of Capt. Benjamin F. Neal. The fort was no puny affair. In addition to the ordnance it had a parade ground and structures for housing livestock and small sailing vessels. The troops lived under canvas (in tents) on the windswept island in what they described as "semi-nomadic conditions."
Fort Semmes became a Federal objective in fall 1863 when Brig. Gen. Thomas E. G. Ransom was ordered to neutralize it as part of a Coastal Bend offensive launched by Gen. Nathaniel Banks. A force of 1,500 Federals supported by a bombardment from USS Monongahela assaulted Semmes at dawn on November 17. With a large body of troops massed to the south and an enthusiastic warship standing offshore, the fort was surrendered forthwith. General Ransom reported the capture of three cannons serviced by a manning of nine officers and eighty-nine enlisted.
Captain Neal was absent from Fort Semmes at its fall. As a prisoner of the Federals, the acting commander, Capt. William Maltby, had good fortune: His brother was a Northern general officer who arranged Maltby's parole from captivity. For having engaged and driven back the Confederate picket line, the fort flag went to a Maine infantry regiment; those colors were returned to Texas in 1928.
After taking Fort Semmes, General Ransom continued his march northward, next attacking Fort Esperanza on Matagorda Island. A garrison was left on Mustang Island. These troops occupied the island until July 1864.