After the fall of New Orleans in April 1862, an 18-month drive began to control Vicksburg and the Mississippi River. Vicksburg's high bluffs, artillery, bayous, and river fortifications made it a formidable strategic position that interrupted Northern troops, supplies, and commerce. Federal forces advanced south from Tennessee and north from the Gulf, but early efforts were checked by Confederate defenses, the destruction of Union supply lines, and defeats such as the repulse at Chickasaw Bayou. Ulysses S. Grant renewed the campaign with operations meant to disrupt Southern communications and draw off Confederate forces, while Benjamin H. Grierson's cavalry raid destroyed rolling stock, bridges, trestles, track, and telegraph lines and lured away Confederate troops. Moving down the west side of the river through Louisiana, Grant crossed at Bruinsburg after David D. Porter positioned gunboats to secure the river at Grand Gulf, then fought east of the river and overwhelmed scattered Confederate forces. Grant then began the final siege of Vicksburg, and Confederate surrender came on July 4, 1863. Five days later Port Hudson fell, completing control of the Mississippi River. The victory opened the river to the North, split the South in two, blocked the movement of men and munitions across the river, dealt a psychological blow to the Confederacy, and ultimately helped lead to Union victory.
