Battle of Gaines' Mill

Battle of Gaines' Mill (First Battle of Cold Harbor)
Part of the American Civil War
Battle of Friday on the Chickahominy Alfred R. Waud, artist, June 27, 1862. Newspaper illustration after the original sketch.
Date June 27, 1862 (1862-06-27) Location Hanover County, Virginia 37°34′44″N 77°17′14″W / 37.5790°N 77.2872°W / 37.5790; -77.2872 Result Confederate victory[1]
Belligerents
United States	Confederate States
Commanders and leaders
George B. McClellan Fitz John Porter	Robert E. Lee
Units involved
Army of the Potomac	Army of Northern Virginia
Strength
34,214[2]	57,018[2]
Casualties and losses
7,337 (1,005 killed, 3,107 wounded, 3,236 missing or captured)[3]	7,993 (1,483 killed, 6,402 wounded, 108 missing or captured)[3]

The Battle of Gaines' Mill, sometimes known as the Battle of Chickahominy River, took place on June 27, 1862, in Hanover County, Virginia, as the third of the Seven Days Battles which together decided the outcome of the Union's 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 Confederates 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' 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 Battle of Cold Harbor nearly two years later.