Vicksburg Assaults

Assaults on Vicksburg After the Battle of the Big Black on May 17, Pemberton retreats into Vicksburg and begins establishing his defense Grant is anxious to finish the job and orders two assaults on May 19 and 22 –The first is relatively hasty, the second more deliberate –Both fail THE SIEGE OF VICKSBURG-- APPROACH OF McPHERSON'S SAPS TO THE REBEL WORKS Harper’s Weekly

Confederate Defenses The Confederates built nine major fortifications that anchored their line –Each covered the roads and the railroad that constituted the best Federal avenues of approach –Rifle pits connecting the major works made the Confederate line more or less continuous “Vicksburg was, then, rather an intrenched camp than a fortified place, owing much of its strength to the difficult ground, obstructed by fallen trees in its front, which rendered rapidity of movement and ensemble [coordination] in an assault impossible.” –Report of Captains Prime and Comstock, Grant’s chief engineers

Terrain facing the Federal Assaults

May 19 Assault Major attack is by Sherman’s corps at the Confederate left- center at Stockade Redan (a V-shaped fortification, open to the rear) Particularly effective fire comes from the Confederate “lunettes” (a small outwork, sometimes crescent-shaped, usually on the flank of a larger fortification) –Green’s lunette and the 27 th Louisiana Lunette provided enfilade fire over the ground in front of the redan Enfilade Fire redan lunette

May 19 Assault

Terrain, obstacles, and fire all worked in concert to stop the Federal attack –“Confederate rifle and artillery fire raked the blue lines from front and flank as they plunged into the ravine– where abatis, wire entanglements, and pits covered with grass mats further broke up the Union formations.” Chris Gabel, Staff Ride Handbook for the Vicksburg Campaign, 162

May 19 Assault Part of Smith’s Brigade did make it to the top, dodging hand grenades and artillery shells the Confederates rolled down on them from the redan –At nightfall they withdrew back to Federal lines –By then their flagstaff was in three pieces and the flag itself had 56 holes in it The 1st Battalion, 13th Infantry lost 43% of its men in the May 19 assault, but by planting its colors, for however briefly, on the top of the slope, it was authorized to claim honors as “First at Vicksburg.”

May 19 Assault Sherman’s corps losses 134 killed, 571 wounded, and 8 missing McPherson’s and McClernand’s corps conducted only limited attacks and lost 23 killed and 206 wounded Confederate casualties probably were less than 200 The failed attack showed the Confederate defenses would not be easily taken, so Grant began planning a larger attack –Wants to try to secure Vicksburg before Johnston can organize a relief force

May 22 Assault This time Grant proceeded the attack with a four-hour artillery bombardment Grant’s plan is for all three of his corps to attack in force –McClernand, however, is the only commander to attack with his entire corps

May 22 Assault McClernand has success at the Railroad Redoubt and threatens South Fort and Square Fort –McClernand needs help from Sherman and McPherson to exploit these opportunities, but he doesn’t get it Sherman’s own attack fails and he calls it off, reportedly saying, “This is murder. Stop those men.” McPherson also makes no headway

May 22 Assault Grant halts the attack after losing 3,200 men –Pemberton lost less than 500 With this defeat, Grant gives up the idea of taking Vicksburg by assault and begins siege tactics

May 22 Assault: McClernand’s Relief McClernand tries to blame Grant, Sherman, and McPherson for the failed attack and issues a congratulatory order to his troops implying that the other corps had failed to do their part and left McClernand’s men to fend for themselves The order is really a thinly disguised press release and when it makes its way into several Northern papers, Grant has the excuse he needs to relieve McClernand –Standing orders required corps commanders to clear press releases through Grant’s headquarters and McClernand had not done so –On June 18, Grant relieves McClernand, sends him back to Illinois, and appoints Edward O. C. Ord to replace him

Thayer’s Approach John Thayer’s brigade had taken part in the unsuccessful assaults on May 19 and 22; advancing up the hill only to be driven back by Confederates positioned at the top. –After the second failure, he began digging a six foot deep trench up the hill. Near the top of the hill, the Federal soldiers began digging a mine under the Confederates. –Vicksburg surrendered before it could be completed.

Thayer’s Approach Federal View Confederate View

OAKOC Observation Avenues of Approach Key Terrain Observation and fields of fire Cover and concealment

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