In November 1862, Confederate General John Bankhead Magruder assumed command of the District of Texas, New Mexico, and Arizona. The Union controlled most of the harbors along the Texas coast, but Magruder quickly changed that with two major assaults on Union defenses. He captured Galveston, Texas, on January 1, 1863, and then drove off a Yankee force at Sabine Pass later that month. After Magruder's forces drove the Union ships away, the Rebels were left with two harbors from which to operate.
In the summer of 1863, the Union commander in the region, General Nathaniel Banks, launched an expedition to retake Sabine Pass. He placed General William B. Franklin in charge of an amphibious force that included four gunboats, 18 transports, and nearly 6,000 troops. They set sail from New Orleans, Louisiana, and arrived off Sabine Pass on September 7. The next day, Franklin called for an invasion of the Confederate band of 47 Irish immigrants commanded by Lieutenant Richard W. "Dick" Dowling, which was holed up inside of Fort Griffin, a stronghold armed with six old smoothbore cannons.
Dowling's men had one major advantage: Their guns were fixed on the narrow channel of Sabine Pass, through which the Yankees would have to sail in order to approach Fort Griffin. The battle commenced in the afternoon, and the Confederate cannons quickly cut into the Union flotilla. The first two ships to go through the pass were badly damaged and ran aground. The troop transports ran into trouble, and one Union ship turned around without firing a shot. Franklin called off the attack and returned to New Orleans.
While the Confederates did not lose a single man, 28 Yankees were killed, 75 were wounded, and 315 were captured. The loss was humiliating for the Union. Franklin was ridiculed, and Dowling's Rebels became heroes. Banks nixed plans for an invasion of east Texas and focused his attention on the Rio Grande Valley.