Vicksburg Siege: Defining Civil War Tactics

1. Vicksburg Siege

2. Definitions • Siege • Blocking the supply lines and escape routes of a city to force it to surrender. • Usually involves one army trapped in a city, slowly running out of food and fresh water, with the opposing army camped outside. • Siege lines • Lines of works and fortifications that are built by both armies during a siege. • The defenders build earthworks to strengthen their position inside a fort or city against assault while the besieging army constructs fortifications to protect siege guns and soldiers from sharpshooters inside the city.

3. Civil War Sieges • Yorktown • Harper’s Ferry • Vicksburg • Port Hudson • Petersburg Federal siege lines at Yorktown

4. Decision to Lay Siege • Following the failure of the May 22 assault, Grant realized that Vicksburg could not be taken by storm and decided to lay siege to the city. • Slowly his army established a line of works around the city and cut Vicksburg off from supply and communications with the outside world. Large “sap rollers” constructed of cane and other materials protected the diggers as they worked at the head of the trenches.

5. Siege Artillery • Normally operated independently of the other combat arms • Formed siege trains that were called to the front only under special circumstances • “We had no siege guns except six thirty-two pounders, and there were none at the West to draw from. Admiral Porter, however, supplied us with a battery of navy-guns of large calibre, and with these, and the field artillery used in the campaign, the siege began.” • Grant, Memoirs

6. Naval Actions during the Siege • Porter fired 11,500 projectiles from his ironclads and mortarboats • He also landed 13 heavy cannon from his gunboats for the Army to use as siege artillery • These fired 4,500 rounds • The Navy also ensured supplies and reinforcements reached Grant’s Army without interference from the Confederates

7. Siege Artillery at Vicksburg • “By the 30th of June there were two hundred and twenty guns in position, mostly light field-pieces, besides a battery of heavy guns belonging to, manned and commanded by the navy. We were now as strong for defence against the garrison of Vicksburg as they were against us…” • Grant, Memoirs Battery Benton

8. Siege Artillery at Vicksburg • “The first thing to do was to get the artillery in batteries where they would occupy commanding positions; then establish the camps, under cover from the fire of the enemy but as near up as possible; and then construct rifle-pits and covered ways, to connect the entire command by the shortest route. The enemy did not harass us much while we were constructing our batteries. Probably their artillery ammunition was short; and their infantry was kept down by our sharpshooters, who were always on the alert and ready to fire at a head whenever it showed itself above the rebel works. “ • Grant, Memoirs

9. Siege lines • “In no place were our lines more than six hundred yards from the enemy. It was necessary, therefore, to cover our men by something more than the ordinary parapet. To give additional protection sand bags, bullet-proof, were placed along the tops of the parapets far enough apart to make loop-holes for musketry. On top of these, logs were put. By these means the men were enabled to walk about erect when off duty, without fear of annoyance from sharpshooters.”   • Grant, Memoirs

10. D- Bombproof G- Head log A- Parapet

11. Siege lines • Federal engineers constructed thirteen approaches and dug a series of trenches measuring almost 15 miles • Part of the plan was to dig close enough to the Confederate fortifications to tunnel underneath them, plant charges of black powder, and destroy the positions

12. Siege lines • Siege lines were built in zig-zag patterns to minimize the effects of enfilading fire

13. Hovey’s Approach

14. Federal Defenses • Grant remained concerned about a counterattack from Johnston and took steps to protect himself • Sherman deployed 34,000 men about 15 miles east of Vicksburg • Cavalry guarded fords on Big Black River and monitored Johnston’s movements Sherman felt, “Every possible motive exists for [Johnston] to come to the relief of Vicksburg.”

15. Milliken’s Bend • There was always the possibility that Pemberton would receive help from the Trans-Mississippi Department, but the poor Confederate unity of effort worked against this • Finally Major General John Walker’s Texas Division began operating on the east side of the Mississippi and attacked Milliken’s Bend on June 7

16. Milliken’s Bend • Even then, support from the Trans-Mississippi was grudging • LTG Dick Taylor had preferred to use Walker against New Orleans, but was overruled by Smith • Taylor complained that “Remonstrances were to no avail.  I was informed that all the Confederate authorities in the east were urgent for some effort on our part in behalf of Vicksburg, and that public opinion would condemn us if we did not try to do something.”  • He insisted “that to go two hundred miles and more away from the proper theatre of action in search of an indefinite something is hard; but orders are orders.”

17. Milliken’s Bend • The Confederates were repulsed by Federal gunboats and black troops in Louisiana and Mississippi regiments • “This was the first important engagement of the war in which colored troops were under fire. These men were very raw, having all been enlisted since the beginning of the siege, but they behaved well.” • Grant, Memoirs African American Monument at Vicksburg

18. Mines • The Federals dug mines under the Confederate lines and packed them with black powder • The Confederates unsuccessfully tried to stop them with counter-mines • The first Federal mine was dug toward the 3rd Louisiana Redan which the Federals called “Fort Hill” • Dug a tunnel three feet wide, 4 feet high, and 40 feet long

19. Mines • On June 25 the Federals detonated 2,200 pounds of explosives and blasted a crater 35 feet wide by 12 feet deep • A soldier in the 3rd Louisiana reported, “Suddenly the earth under our feet gave a convulsive shudder and with a muffled roar, a mighty column of earth, men, poles, spades, and guns arose many feet in the air. About fifty lives were blotted out in that instant.”

20. Mines • The 45th Illinois led the Federal assault but was repulsed • On July 1, the Federals detonated a second mine, but there was no attempt at an assault • Mining efforts continued right up to the surrender Confederate defenders threw hand grenades down on to the Federals

21. Surrender • On June 22, Pemberton received a letter signed by “Many Soldiers” stating, “If you can’t feed us, you had better surrender us” and warning, “The army is ripe for mutiny unless it can be fed.” • On July 1, Pemberton held a council of war and none of his generals expressed any hope that Johnston would come to Vicksburg’s aid • Bowen and Smith recommended surrender

22. Surrender • On July 3 Pemberton sent a note to Grant proposing an armistice to arrange “terms for the capitulation of Vicksburg” • At first Grant proposed unconditional surrender, but he eventually offered terms • On July 4, Pemberton surrendered after a 47 day siege Grant receiving Pemberton’s note

23. Surrender • Confederate soldiers had to give up their arms, but they would be paroled (allowed to go free if they promised not to fight until properly exchanged later for Federal prisoners) • Officers were allowed to keep their side arms, clothing, and one horse each • Some 29,500 men were surrendered • By allowing parole, Grant prevented himself from being encumbered by so many prisoners • He also assumed many of the despondent men would have no interest in fighting again even if exchanged later

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