This Week in the Civil War - 568
Confederate General Joseph Johnston had been in command of all Confederate troops in Mississippi, including those at Vicksburg, for less than a week when Ulysses Grant decided to attack Jackson, the state’s capital, before assaulting Vicksburg.
With only 12,000 troops Joseph Johnston had to abandon the city, evacuating critical supplies and withdrawing to the north. On Thursday, May 14, 1863 after overwhelming the two Confederate brigades left behind to affect a delaying action, Federal forces occupied Jackson.
Johnston knew that Union forces under John McClernand occupied parts of the rail line linking Jackson to Vicksburg, thus separating Johnston’s forces from John Pemberton’s beleaguered Confederates at Vicksburg. Grant now had the latitude to turn west from Mississippi’s capital city and move directly against Vicksburg, while preventing Johnston and Pemberton’s forces from uniting.