Battle of Port Gibson The Battle of Port Gibson was fought near Port Gibson , Mississippi , on May 1 , 1863 , between Union and Confederate forces during the Vicksburg Campaign of the American Civil War . The Union Army was led by Maj . Gen . Ulysses S . Grant , and they were victorious . Background . Grant launched his campaign against Vicksburg , Mississippi , in the spring of 1863 , starting his army south from Milliken ' s Bend on the west side of the Mississippi River . He intended to storm Grand Gulf , while his subordinate Maj . Gen . William T . Sherman deceived the main army in Vicksburg by feigning an assault on the Yazoo Bluffs . Grant would then detach the XIII Corps to Maj . Gen . Nathaniel P . Banks at Port Hudson , Louisiana , while Sherman hurried to join Grant and James B . McPherson for an inland move against the railroad . The Union fleet , however , failed to silence the Confederate batteries at Grand Gulf . Grant then sailed farther south and began crossing at Bruinsburg , Mississippi , on April 30 . Sherman ' s feint against the Yazoo Bluffs — the Battle of Snyder ' s Bluff — was a complete success , and only a single Confederate brigade was detached south . The only Confederate cavalry in the area , Wirt Adams ' s cavalry regiment , had been ordered away to pursue Grierson ' s raiders , so Maj . Gen . John S . Bowen performed a reconnaissance in force to determine the Federals ' intentions . Bowen moved south from Grand Gulf with Green ' s Brigade and took up a position astride the Rodney road just southwest of Port Gibson near Magnolia Church . A single brigade of reinforcements from Vicksburg under Brig . Gen . Edward D . Tracy arrived later and was posted across the Bruinsburg Road two miles north of Green ' s position . Baldwin ' s Brigade arrived later and was positioned in support of Green ' s Brigade . One - hundred - foot - tall ( ) hills separated by nearly vertical ravines choked with canebrakes and underbrush rendered Bowen ' s position tenable , despite the overwhelming Union force headed his way . The absence of Confederate cavalry would have a major impact on the unfolding campaign . Had Bowen been assured that the Federals were landing at Bruinsburg and not Rodney , he could have taken a position on the bluffs above Bruinsburg , denying Grant ' s army a bridgehead into the interior . Federal efforts to push rapidly inland were exacerbated by the fact that Maj . Gen . John A . McClernand had forgotten to issue rations to the men . Despite the resulting delay , the Army of the Tennessee moved onto the river bluffs unopposed and pushed rapidly towards Port Gibson . Just after midnight on May 1 , advanced elements of the 14th Division under Brig . Gen . Eugene A . Carr engaged Confederate pickets near the Shaifer House . Sporadic skirmishing and artillery fire continued until 3 a . m . Wary of Tracy ' s Brigade to the north , McClernand posted Brig . Gen . Peter J . Osterhaus ' s 9th Division facing that direction . Having developed each other ' s positions , both sides settled down and waited for first light . Battle . General Carr scouted the ground before him and determined that a frontal assault through the canebrakes would be fruitless . He devised a turning movement whereby one brigade would move slowly forward through the canebrake while the second brigade would descend into the Widow ' s Creek bottoms and from there strike for the Confederate left flank . Brig . Gen . Alvin P . Hovey ' s 12th Division arrived and surged forward just as Carr ' s men were storming the Confederate position . Both flanks having been turned , Green ' s men broke and ran . McClernand stopped to reorganize and then , always the politician , launched into a series of grandiose speeches until Grant pointed out that the Confederates had merely withdrawn to a more tenable position . Reinforced by Brig . Gen . A . J . Smith ' s 10th Division and Stevenson ' s Brigade of McPherson ' s XVII Corp , McClernand resumed the pursuit . With 20 , 000 men crowded into a front , McClernand ' s plan appeared to be to force his way past the Confederate line . A flanking assault by Col . Francis Cockrell ' s Missourians crumpled the Federal right flank and gave McClernand pause . Sundown found the two sides settling into a stalemate along a broad front on the Rodney Road several miles from Port Gibson . On the Bruinsburg Road front , Osterhaus had been content to pressure Tracy ' s command with federal sharpshooters and artillery , occasionally launching an unsupported regiment against the Confederate line . Maj . Gen . James B . McPherson showed up late in the afternoon with John E . Smith ' s brigade . Donning a cloak to disguise his rank , he reviewed the front lines and quickly devised a turning movement that would render untenable the entire Confederate right flank . Twenty minutes after the troops had been staged for the assault , the Confederates were retreating into the Bayou Pierre bottoms , having left behind several hundred prisoners . The road to his rear now threatened , Bowen commenced retreating through Port Gibson to the north shore of Bayou Pierre . Aftermath . On May 2 , Grant quickly maneuvered Bowen out of position by sending McPherson to cross the Bayou Pierre at a ford several miles upstream . Struck with the realization that McPherson could cut him off from the bridge over the Big Black River , Bowen ordered the formidable defenses at Grand Gulf abandoned , the magazine exploded , and the heavy artillery destroyed . Union gunboats , investigating the nature of the explosion , arrived and took Grand Gulf without a shot . Grant understood the nature of the explosion and rode to Grand Gulf with a small escort , enjoying his first bath in weeks , and celebrating the capture of what would become his central supply depot as he moved inland . As he relaxed , he caught up on correspondence , including a message from Banks that he was nowhere near Port Hudson . Grant ' s plan to detach McClernand to Banks would have to wait . Too late to do anything more than affirm Bowen ' s decision , Maj . Gen . William W . Loring arrived and took command . Heavy rear - guard activity took place as the Confederates scrambled to remove their force across the narrow bridge . Advanced elements of the XVII Corps arrived in time to save the bridge from destruction . The ragtag army that had fought so well at Port Gibson would not rest until they had entered the Warrenton fortifications nearly ten miles away . Here they began improving the fortifications along the roads to Vicksburg , expecting that Grant would be close behind . Grant , however , would have other plans ; the roads on the west bank of the Big Black River were open all the way to the Mississippi state capital and the critical rail link to Vicksburg . Against this target , Grant poised his army to strike .