By late May 1863 United States naval forces were actively engaged against their Confederate foes. On the Mississippi River, on May 21, a Federal flotilla assaulted Confederate held, Yazoo City, Mississippi, forcing the evacuating Confederates to destroy their shops and naval yard, including two steamboats and a partially completed gunboat.
The following day Federal gunboats and mortars supported Ulysses Grant’s failed frontal assault against Vicksburg’s defenses. On May the 24th, Federal marines burned the town of Austin, Mississippi in reprisal for Confederates firing on the Union fleet.
On the following day, May the 25, near Port Hudson, Federal forces captured the Confederate steamers Starlight and Red Chief. In a war of attrition, the Union Navy was slowly, but surely, clearing the inland waterways of Confederate naval forces.