Thomas E. Corcoran (October 12, 1839 – March 12, 1904) was a Union Navy sailor in the American Civil War and a recipient of the United States military's highest decoration, the Medal of Honor, for his actions during the Siege of Vicksburg.

Under heavy fire from a Confederate artillery battery, Corcoran and three other men swam back and forth between the riverbank and the sinking ship, helping crewmen who could not swim reach shore.

He re-enlisted the next month, on October 22, again for a three-year term, and was posted as a landsman to Cincinnati for service on the upper Mississippi River.

Between Cincinnati and the two guns was a Confederate eleven-piece heavy artillery battery which, from its position atop a bluff, had command over that entire stretch of the river.

Unbeknownst to them, the battery's guns had been removed from view by simply lowering them from their carriages, both to protect them from the fire of ships on the river and to deceive the Union forces.

The commander of the battery had discovered the Union signal code, and when he intercepted a message describing Cincinnati's mission, he had the guns re-assembled during the night and concealed them in brush.

They then reboarded Cincinnati, hastily repaired a small boat which had been damaged by the Confederate fire, and loaded it with men who were too badly wounded to be dragged through the water.

Serving bravely during this action, Corcoran was conspicuously cool under the fire of the enemy, never ceasing to fight until this proud ship went down, "her colors nailed to the mast.