 The subsequent two weeks on the peninsula were mostly quiet . On June 25 , though , a surprise attack by McClellan began a series of six major battles over the next week near Richmond — the Seven Days Battles . On the first day , as Lee led the Army of Northern Virginia toward the Union lines , McClellan preempted him with an attack at Oak Grove . Lee 's men successfully warded off the Union assault , and Lee continued with his plans . The next morning , the Confederates attacked the Army of the Potomac at Mechanicsville . Union forces turned back the Confederate onslaught , inflicting heavy losses . After Mechanicsville , McClellan 's army withdrew to a position behind Boatswain 's Swamp . There , on June 27 , the Union soldiers suffered another Confederate attack , this time at Gaines 's Mill . In the resulting battle , the Confederates launched numerous failed charges , until a final concerted attack broke the Union line , resulting in the only clear Confederate victory during the Seven Days . The action at Garnett 's and Golding 's Farm , fought next , was merely a set of skirmishes . Lee attacked the Union Army at the Battle of Savage 's Station on June 29 and the battles of Glendale and White Oak Swamp June 30 , but all three battles were inconclusive . After this series of conflicts that inflicted thousands of casualties on both armies , McClellan began to position his forces to an imposing natural position atop Malvern Hill . 
