The Battle of Seven Pines, also known as the Battle of Fair Oaks or Fair Oaks Station, takes place on May 31 and June 1, 1862, in Henrico County, Virginia, as part of the Peninsula Campaign of the American Civil War.

It is the culmination of an offensive up the Virginia Peninsula by Union Maj. Gen. George B. McClellan, in which the Army of the Potomac reaches the outskirts of Richmond.

On May 31, Confederate General Joseph E. Johnston attempts to overwhelm two Federal corps that appear isolated south of the Chickahominy River.

The Confederate assaults, although not well coordinated, succeed  in driving back the IV Corps and inflicting heavy casualties. Reinforcements arrive, and both sides feed 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 crosses the rain-swollen river on Grapevine Bridge), the Federal position is finally stabilized.

Gen. Johnston is seriously wounded during the action, and command of the Confederate army devolves temporarily to Maj. Gen. G.W. Smith.

On June 1, the Confederates renew their assaults against the Federals, who have brought up more reinforcements, but make little headway.

Both sides claim victory.

Although the battle is tactically inconclusive, it is the largest battle in the Eastern Theater up to this time (and second only to Shiloh in terms of casualties thus far, about elbven thousand total).

Gen. Johnston's injury also has profound influence on the war: it leads to the appointment of Robert E. Lee as Confederate commander.

The more aggressive Lee initiates the Seven Days Battles, leading to a Union retreat in late June.

Seven Pines therefore marksthe closest Union forces come to Richmond in this offensive.