The Battle of Seven Pines, also known as the Battle of Fair Oaks or Fair Oaks Station, took place on May 31 and June 1, 1862, in Henrico County, Virginia, nearby Sandston, as part of the Peninsula Campaign of the American Civil War. It was the culmination of an offensive up the Virginia Peninsula by Union Maj. Gen. George B. McClellan, in which the Army of the Potomac reached the outskirts of Richmond.

On May 31, Confederate General Joseph E. Johnston attempted to overwhelm two Federal corps that appeared isolated south of the Chickahominy River. The Confederate assaults, although not well coordinated, succeeded in driving back the IV Corps and inflicting heavy casualties. Reinforcements arrived, and both sides fed more and more troops into the action. Supported by the III Corps and Maj. Gen. John Sedgwick's division of Maj. Gen. Edwin V. Sumner's II Corps (which crossed the rain-swollen river on Grapevine Bridge), the Federal position was finally stabilized. Gen. Johnston was seriously wounded during the action, and command of the Confederate army devolved temporarily to Maj. Gen. G.W. Smith. On June 1, the Confederates renewed their assaults against the Federals, who had brought up more reinforcements, but made little headway. Both sides claimed victory.Although the battle was tactically inconclusive, it was the largest battle in the Eastern Theater up to that time (and second only to Shiloh in terms of casualties thus far, about 11,000 total). Gen. Johnston's injury also had profound influence on the war: it led to the appointment of Robert E. Lee as Confederate commander. The more aggressive Lee initiated the Seven Days Battles, leading to a Union retreat in late June. Seven Pines therefore marked the closest Union forces came to Richmond in this offensive.

The Peninsula campaign (also known as the Peninsular campaign) of the American Civil War was a major Union operation launched in southeastern Virginia from March through July 1862, the first large-scale offensive in the Eastern Theater. The operation, commanded by Maj. Gen. George B. McClellan, was an amphibious turning movement against the Confederate States Army in Northern Virginia, intended to capture the Confederate capital of Richmond. McClellan was initially successful against the equally cautious General Joseph E. Johnston, but the emergence of the more aggressive General Robert E. Lee turned the subsequent Seven Days Battles into a humiliating Union defeat.

McClellan landed his army at Fort Monroe and moved northwest, up the Virginia Peninsula. Confederate Brig. Gen. John B. Magruder's defensive position on the Warwick Line caught McClellan by surprise. His hopes for a quick advance foiled, McClellan ordered his army to prepare for a siege of Yorktown. Just before the siege preparations were completed, the Confederates, now under the direct command of Johnston, began a withdrawal toward Richmond. The first heavy fighting of the campaign occurred in the Battle of Williamsburg, in which the Union troops managed some tactical victories, but the Confederates continued their withdrawal. An amphibious flanking movement to Eltham's Landing was ineffective in cutting off the Confederate retreat. In the Battle of Drewry's Bluff, an attempt by the U.S. Navy to reach Richmond by way of the James River was repulsed.

As McClellan's army reached the outskirts of Richmond, a minor battle occurred at Hanover Court House, but it was followed by a surprise attack by Johnston at the Battle of Seven Pines or Fair Oaks. The battle was inconclusive, with heavy casualties, but it had lasting effects on the campaign. Johnston was wounded by a Union artillery shell fragment on May 31 and replaced the next day by the more aggressive Robert E. Lee, who reorganized his army and prepared for offensive action in the final battles of June 25 to July 1, which are popularly known as the Seven Days Battles. The end result was that the Union army was unable to enter Richmond, and both armies remained intact.