19 September – On this day

The Third Battle of Winchester (or Battle of Opequon), was fought in Winchester, Virginia, on this day in 1864, during the Valley Campaigns of 1864 in the American Civil War.

As Confederate Lt. Gen. Jubal A. Early raided the B&O Railroad at Martinsburg, WV, Union Maj. Gen. Philip H. Sheridan advanced toward Winchester along the Berryville Pike with the VI Corps and XIX Corps, crossing Opequon Creek. The Union advance was delayed long enough for Early to concentrate his forces to meet the main assault, which continued for several hours. Casualties were very heavy. The Confederate line was gradually driven back toward the town. Mid-afternoon, the VIII Corps and the cavalry turned the Confederate left flank. Early ordered a general retreat. Because of its size, intensity, serious casualties among the general officers on both sides, and its result, many historians consider this the most important conflict of the Shenandoah Valley.