Battle of Gaines ' s Mill The Battle of Gaines ' s Mill , sometimes known as the First Battle of Cold Harbor or the Battle of Chickahominy River , took place on June 27 , 1862 , in Hanover County , Virginia , as the third of the Seven Days Battles ( Peninsula Campaign ) of the American Civil War . Following the inconclusive Battle of Beaver Dam Creek ( Mechanicsville ) the previous day , Confederate General Robert E . Lee renewed his attacks against the right flank of the Union Army , relatively isolated on the northern side of the Chickahominy River . There , Brig . Gen . Fitz John Porter ' s V Corps had established a strong defensive line behind Boatswain ' s Swamp . Lee ' s force was destined to launch the largest Confederate attack of the war , about 57 , 000 men in six divisions . Porter ' s reinforced V Corps held fast for the afternoon as the Confederate attacked in a disjointed manner , first with the division of Maj . Gen . A . P . Hill , then Maj . Gen . Richard S . Ewell , suffering heavy casualties . The arrival of Maj . Gen . Stonewall Jackson ' s command was delayed , preventing the full concentration of Confederate force before Porter received some reinforcements from the VI Corps . At dusk , the Confederates finally mounted a coordinated assault that broke Porter ' s line and drove his men back toward the Chickahominy river . The Federals retreated across the river during the night . The Confederates were too disorganized to pursue the main Union force . Gaines ' s Mill saved Richmond for the Confederacy in 1862 ; the tactical defeat there convinced Army of the Potomac commander Maj . Gen . George B . McClellan to abandon his advance on Richmond and begin a retreat to the James River . The battle occurred in almost the same location as the 1864 Battle of Cold Harbor and had a similar number of total casualties . Background . McClellan ' s Army of the Potomac had pushed to within a few miles of the Confederate capital of Richmond and had stalled following the Battle of Seven Pines in late May 1862 . Lee wanted to take the initiative , believing that remaining on the strategic defensive would play into Union hands and allow the Confederacy to be worn down . He planned to shift his 90 , 000 - man Confederate army to the north of Richmond , and attack McClellan ' s right flank . The Confederate cavalry under the command of Maj . Gen . J . E . B . Stuart had ridden around McClellan ' s army , confirming that the flank was open — not anchored on Totopotomoy Creek — and vulnerable . Lee planned to use Maj . Gen . Stonewall Jackson ' s force , transported by rail from the Shenandoah Valley , to attack on McClellan ' s right and rear , while the remainder of his army under Maj . Gens . A . P . Hill , James Longstreet , and D . H . Hill attacked from the direction of Mechanicsville . The Seven Days Battles began with a Union attack in the minor Battle of Oak Grove on June 25 , but the first major battle started the next day when Lee launched a large - scale assault against McClellan at the Battle of Beaver Dam Creek ( or Mechanicsville ) . Lee attacked Porter ' s V Corps north of the Chickahominy , while the bulk of the Union Army was relatively unoccupied south of the river . Although this battle was a tactical victory for the Union , McClellan realized that he could not keep Porter ' s corps in place with Jackson threatening his flank . He ordered Porter to begin a withdrawal and at the same time decided to change the army ' s base of supply from White House on the Pamunkey River to Harrison ' s Landing on the James River . ( This decision was fatal to McClellan ' s campaign because by abandoning the railroad that led from the Pamunkey , he would no longer be able to supply his planned siege of Richmond with the necessary heavy artillery . ) Several of McClellan ' s subordinates urged him to attack the Confederate division of Maj . Gen . John B . Magruder south of the Chickahominy , but he feared the vast numbers of Confederates he believed to be before him and failed to capitalize on the overwhelming superiority he actually held on that front . Magruder assisted in this misapprehension by ordering frequent , noisy movements of small units back and forth and by using groups of slaves with drums to simulate large marching columns . Furthermore , the Union Army Balloon Corps , which had performed the only aerial observation during the Peninsula Campaign , was now joined by a Confederate competitor . Capt . Langdon Cheves of South Carolina had constructed a multicolored balloon of dress silk obtained from Charleston and Savannah , which sailed aloft tethered to a boxcar on the York River Railroad , manned by Maj . Edward Porter Alexander . The appearance of this balloon reinforced McClellan ' s fear that the Confederates were planning for an offensive against his left flank . For the second day , the Confederates were able to continue fooling McClellan south of the river by employing minor diversionary attacks to command the attention of 60 , 000 Federal troops while the heavier action occurred north of the river . The order to Porter ' s corps came just before dawn and they did not have adequate time to prepare a strong rear guard for the withdrawal , resulting in numerous men from Brig . Gen . George A . McCall ' s division being captured by the advancing Confederates . Porter selected a new defensive line on a plateau behind Boatswain ' s Swamp , just to the southeast of a mill owned by Dr . William F . Gaines . It was a strong position , with two divisions laid out in a semicircle — Brig . Gen . George W . Morell on the left and Brig . Gen . George Sykes on the right — and two divisions in reserve — Brig . Gen . George A . McCall and Brig . Gen . Henry W . Slocum , the latter on loan to Porter from Brig . Gen . William B . Franklin ' s VI Corps . Slocum ' s division had not crossed the river by the start of the battle , held up by McClellan ' s concern about an impending attack on Franklin ' s front . Lee ' s offensive plan for June 27 was similar to that of the preceding day . He would use A . P . Hill ' s and Longstreet ' s divisions to pressure Porter ' s corps as it withdrew , while Stonewall Jackson , augmented by D . H . Hill ( Jackson ' s brother - in - law ) , hit Porter ' s right and rear . The combined effort of all of Lee ' s force was destined to be the largest Confederate attack of the war , about 57 , 000 men in six divisions . Lee traveled to Walnut Grove Church to meet with Jackson and describe the plan , which called for Jackson to march toward Old Cold Harbor , and then south beyond Porter ' s flank . Unfortunately , Lee made incorrect assumptions about Porter ' s disposition . He assumed that the V Corps would defend the line of Powhite Creek , somewhat to the west of Porter ' s actual location . Battle . The first actions of the battle occurred between noon and 1 p . m . on June 27 after D . H . Hill ' s division reached Old Cold Harbor , where it was scheduled to link up with Stonewall Jackson ' s command . Hill pushed through the crossroads with two brigades , which encountered unexpected infantry fire . Seeking to suppress the fire , he brought forward the Jeff Davis Battery from Alabama , but it was soon outgunned by two six - gun batteries manned by U . S . regulars from Brig . Gen . George Sykes ' s division . Hill was surprised at the level of resistance and also that he seemed to be meeting the front of the Union force , not the expected flank , so he determined to wait for Jackson ' s arrival before moving further . The noise from this engagement failed to reach General Lee at his headquarters , the house owned by William Hogan , named " Selwyn " . A . P . Hill ' s division had moved across Beaver Dam Creek early in the morning , finding the former Union line lightly defended . As they proceeded eastward and approached Gaines ' s Mill at about the time that D . H . Hill ' s men were engaged , Porter formally asked McClellan to send Slocum ' s division across the Chickahominy over Alexander ' s Bridge to support him . Hill ' s lead brigade , under Brig . Gen . Maxcy Gregg , was held up by skirmishers from Col . Hiram Berdan ' s 1st U . S . Sharpshooters and the 9th Massachusetts Infantry . By early afternoon , he ran into strong opposition by Porter , deployed along Boatswain ' s Creek and the swampy terrain was a major obstacle against the advance . Attacks by the brigades of Brig . Gens . Gregg , Dorsey Pender , Joseph R . Anderson , and Lawrence O ' Bryan Branch made little headway . A particularly bloody engagement occurred as the 1st South Carolina Rifles attacked a Massachusetts battery , but were repulsed by Zouaves of the 5th New York , which inflicted 57 % casualties ( 76 killed , 221 wounded , and 58 missing ) on the South Carolinians , the greatest Confederate regimental losses of the day . Instead of pursuing a fleeing enemy , as his orders had directed , A . P . Hill had attacked an entrenched Union position , losing about 2 , 000 of his 13 , 200 men in the failed attempt . Combined with his attacks at Mechanicsville the previous day , the Light Division had lost over a quarter of its men . General McClellan was encouraged by the telegrams Porter sent back to his headquarters a few miles to the rear . He replied , " If the enemy are retiring and you are a chasseur , pitch in . " He also told Franklin to cross the river over the Duane bridge and attack the enemy ' s flank if he saw a chance , but he was dismayed to hear that the VI Corps commander had destroyed the bridge for fear of a possible enemy attack . At the same time , Brig . Gen . Edwin V . Sumner of the II Corps reported enemy activity in his front . McClellan ' s optimism was dashed and he ordered that his headquarters equipment be packed up in preparation for the retreat . On the Confederate side , General Lee had been an active participant in the failed assault , rallying his troops too close to the front for their comfort . As Longstreet arrived to the southwest of A . P . Hill , he saw the difficulty of attacking over such terrain and delayed until Stonewall Jackson could attack on Hill ' s left . For the second time in the Seven Days , however , Jackson was late . A guide from the 4th Virginia Cavalry , Pvt . John Henry Timberlake , had misunderstood Jackson ' s intent and led him down the wrong road . After they counter - marched , losing about an hour , Jackson ' s troops found the road to Old Cold Harbor obstructed by trees felled by the retreating Union army and were harassed by sharpshooters , delaying their arrival . The first of Jackson ' s command to reach the battlefield was the division of Maj . Gen . Richard S . Ewell , who was met by Lee ' s aide , Walter Taylor , and instructed to move into action immediately . Lee was concerned that Porter would counterattack the weakened troops of A . P . Hill , so he ordered Longstreet to conduct a diversionary attack to stabilize the lines until Jackson ' s full command could arrive and attack from the north . In Longstreet ' s attack , Brig . Gen . George E . Pickett ' s brigade attempted a frontal assault and was beaten back under severe fire with heavy losses . Pickett himself was wounded in the shoulder . Confederate President Jefferson Davis was among the party witnessing Pickett ' s failed attempt . Ewell began his attack immediately , around 3 : 30 p . m . , without waiting for his entire division to come on line . General Lee ' s instructions were to advance along the same axis used by the brigades of Gregg and Branch , to maintain the momentum of the attack . He sent in his lead brigade , Louisianans under Col . Isaac Seymour , commanding in Maj . Gen . Richard Taylor ' s absence for medical reasons . Seymour was relatively inexperienced and his troops became confused in the woods and bogs of Boatswain ' s Swamp . Their confusion increased when Col . Seymour was killed by a Union rifle volley . Maj . Roberdeau Wheat , the colorful leader of the Louisiana Tigers Battalion , moved to the front to lead the brigade , but he was also killed with a bullet through his head . The Louisiana Brigade withdrew from the battle . Ewell ' s attack continued with two regiments from the brigade of Brig . Gen . Isaac R . Trimble , but they could not advance beyond the swamp , falling with about 20 % casualties . Porter was starting to receive reinforcements from Slocum ' s division and he brought forward troops to feed into gaps in his line . However , despite telegrams from Porter for more assistance , General McClellan gave no thought to the advantages of a counterattack . He asked his corps commanders south of the river whether they had any troops they could spare . When no one volunteered , he directed Sumner of the II Corps to send two brigades — about one tenth of the army — across the river , but because of the distances involved they would not reach the scene for another three hours . When Stonewall Jackson finally reached Old Cold Harbor , weary from the marching and counter - marching , he began to arrange his troops and those of D . H . Hill to trap the Federals he expected to be driven east by Longstreet and A . P . Hill . He soon received instructions from General Lee that informed him of the current situation and he began to prepare his command to assault the main Federal line . Faulty staff work prevented his men from moving forward for over an hour . While Jackson rode back and forth distractedly , his chaplain , Maj . Robert L . Dabney , took the initiative to find the divisions of Brig . Gens . William H . C . Whiting and Charles S . Winder and corrected the garbled instructions they had received . Generals Lee and Jackson met on the Telegraph Road to coordinate a final assault across the entire Federal line . Lee ' s assault at 7 p . m . was conducted by 16 brigades , about 32 , 100 men . Porter had about 34 , 000 men to defend the line , but many of these were worn out from the previous attacks and command cohesion was hampered by feeding isolated reinforcements into the line to fill gaps . Nevertheless , they had the advantages of good defensible terrain and superiority in artillery . The Confederates were not able to advance simultaneously in a neat battle line over the 2 . 25 - mile front , but rushed forward and were repulsed intermittently in smaller unit actions . On the Confederate left , the assault by D . H . Hill ' s division met heavy resistance from the regulars of Sykes ' s division around the McGehee house . In the center , the Georgians of Brig . Gen . Alexander R . Lawton ' s brigade were in their first battle . They pushed forward with the assistance of the Stonewall Brigade of Winder ' s division , along with Elzey ' s and Trimble ' s of Ewell ' s division . The Confederate right was opposed by the most difficult terrain , a quarter - mile open wheatfield that sloped down to Boatswain ' s Swamp and then faced two lines of Union defenders on higher ground . James Longstreet wrote in his report , " I was , in fact , in the position from which the enemy wished us to attack him . " As the sun was starting to go down , William Whiting ' s division achieved the breakthrough on Longstreet ' s front . Brig . Gen . John Bell Hood ' s Texas Brigade move forward swiftly and aggressively and broke a hole in the line . Pickett ' s brigade also succeeded in its second assault of the day . Confederate breakthroughs on their center and right could not be countered and the Union line crumbled . Sykes ' s regulars conducted an orderly withdrawal from the McGehee house to Grapevine Bridge . The Union brigades of Brig . Gens . Thomas F . Meagher and William H . French arrived from the II Corps , too late to help other than as a rear guard for Porter ' s retreat . A battalion of the 5th U . S . Cavalry under Captain Charles J . Whiting made a desperate charge against the Texas Brigade , but was forced to surrender after heavy losses . By 4 a . m . on June 28 , Porter withdrew across the Chickahominy , burning the bridges behind him . Aftermath . Gaines ' s Mill was an intense battle , the largest of the Seven Days and the only clear - cut Confederate tactical victory of the Peninsula Campaign . Union casualties from the 34 , 214 engaged were 6 , 837 ( 894 killed , 3 , 107 wounded , and 2 , 836 captured or missing ) . Of the 57 , 018 Confederates engaged , losses totaled 7 , 993 ( 1 , 483 killed , 6 , 402 wounded , 108 missing or captured ) . Since the Confederate assault was conducted against only a small portion of the Union Army ( the V Corps , one fifth of the army ) , the army emerged from the battle in relatively good shape overall . Lee ' s victory , his first of the war , could have been more complete if it were not for the mishaps of Stonewall Jackson . Historian Stephen W . Sears speculates that it were not for Jackson ' s misdirected march and his poor staff work , the major assault that Lee unleashed at 7 p . m . could have occurred three or four hours earlier . This would have put Porter in grave jeopardy , without any last - minute reinforcements and the cover of darkness . He quotes Edward Porter Alexander , prominent Confederate artillery officer and postwar historian : " Had Jackson attacked when he first arrived , or during A . P . Hill ' s attack , we would have had an easy victory — comparatively , & would have captured most of Porter ' s command . " Although McClellan had already planned to shift his supply base to the James River , his defeat unnerved him and he precipitously decided to abandon his advance on Richmond and begin the retreat of his entire army to the James . Gaines ' s Mill and the Union retreat across the Chickahominy was a psychological victory for the Confederacy , signaling that Richmond was out of danger . Battlefield preservation . The only preserved portion of the Gaines ' s Mill battlefield for nearly 150 years was a 60 - acre section of the battlefield under National Park Service control around the Watt House . This tract is only a small fraction of the more than 2 , 000 acres that comprises the battlefield . In 2011 , two preservation efforts were completed by the Richmond Battlefields Association and the Civil War Trust — the first preservation successes at Gaines ' s Mill since before World War II . This new 285 - acre " Longstreet Attack " tract greatly expanded the amount of preserved land at Gaines ' s Mill . The Civil War Trust has saved 314 acres at Gaines ’ Mill to date .