The Battle of Grand Gulf was fought on April 29, 1863, during th: In late November, about 40,000 Union infantry commanded by Major General Ulysses S. Grant began moving south towards Vicksburg from a starting point in Tennessee.  Grant ordered a retreat after a supply depot and part of his supply line were destroyed during the Holly Springs Raid on December 20 and Forrest's West Tennessee Raid.  Meanwhile, another arm of the expedition under the command of Major General William T. Sherman left Memphis, Tennessee, on the same day as the Holly Springs Raid and traveled down the Mississippi River.  After diverting up the Yazoo River, Sherman's men began skirmishing with Confederate soldiers defending a line of hills above the Chickasaw Bayou.  A Union attack on December 29, was defeated decisively at the Battle of Chickasaw Bayou, and Sherman's men withdrew on January 1, 1863.[8]