Halleck slowly marched his army to take Corinth, entrenching each night.[166] Meanwhile, Beauregard pretended to be reinforcing, sent "deserters" to the Union Army with that story, and moved his army out during the night, to Halleck's surprise when he finally arrived at Corinth on May 30.[167]
Halleck divided his combined army and reinstated Grant as field commander of the Army of the Tennessee on July 11.[168]
Later that year, on September 19, Grant's army defeated Confederates at the Battle of Iuka, then successfully defended Corinth, inflicting heavy casualties.[169] On October 25, Grant assumed command of the District of the Tennessee.[170] In November, after Lincoln's preliminary Emancipation Proclamation, Grant ordered units under his command to incorporate former slaves into the Union Army, giving them clothes, shelter, and wages for their services.[171] Grant held western Tennessee with almost 40,000 men.[172]

Vicksburg campaign (1862–1863)
Further information: Vicksburg Campaign and General Order No. 11 (1862)
Grant's successful gamble: Porter's gunboats night ran the Confederate gauntlet at Vicksburg on the Mississippi River.Published 1863
The Union capture of Vicksburg, the last Confederate stronghold on the Mississippi River, was vital, and would split the Confederacy in two.