Battle of Mustang Island

Following the battle of Brownsville, the Union army consolidated a garrison there under Major General Napoleon J. T. Dana. Major General Nathaniel P. Banks then planned to move against Corpus Christi. Banks directed Brigadier General Thomas E. G. Ransom on an expedition against a Confederate earthen fortification on Mustang Island known as Fort Semmes. The Confederate garrison, of less than 100 men, was composed of detachments from the 3rd Texas State Militia under Major George O. Dunaway and the 8th Texas Infantry under Captain William N. Maltby.

Ransom’s men made a forced march against Fort Semmes which was occupied by men from the 8th Texas Infantry and 3rd Texas State Militia. The Union advance encountered Confederate skirmishers on November 17. Ransom’s men fired one volley causing the Texas skirmishers to retreat back into Fort Semmes. Ransom deployed the 13th Maine and 15th Maine infantry regiments in line of battle while the USS Monongahela fired into the fort form off shore. Fort Semmes’ small garrison was not prepared for open battle and the fighting was over shortly after the attack commenced. Major Dunaway decided upon an unconditional surrender of the entire garrison rather than making an attempt to fight their way back to the mainland.

Major General Cadwallader C. Washburn arrived at the head of the Union expedition on the Texas Coast. Washburn next led Union forces to capture Fort Esperanza on November 30, 1863.