Vicksburg was described as the ‘Gibraltar of the Confederacy’; built on a heavily fortified bluff overlooking the Mississippi, its approaches comprised a complex maze of swamp and bayou which bemired one Union offensive after another. In spring 1863, Union Commander Grant ordered a passable route built down the western approaches of the Mississippi. By the middle of April, he was ready, and on 16 April, ordered Admiral Porter to run by the Vicksburg’s batteries with supplies and troop transports. This achieved, conveyance across the Mississippi was effected on 29 April, despite bombardment from batteries at Grand Gulf. Overcoming Confederate resistance en route at Port Gibson, Grant advanced to Hankinson’s Ferry. Learning there that General Pemberton’s Confederates blocked his direct route forward, Grant then swerved east, overcoming Confederate forces at Raymond and Jackson, and cutting supply routes to Vicksburg. Turning west, defeat of Pemberton at Champion’s Hill (16 May) opened the way to ‘Gibraltar’s’ rear.
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