The Largest Battles of the Civil War

Nearly five months after the Union victory at the Battle of Shiloh, the Confederacy racked up a major victory at the Second Battle of Bull Run, also known as the Battle of Second Manassas. This came about a year after the first Battle of Bull Run – the first full-scale battle of the Civil War – which also resulted in a Confederate win. In the second, larger battle, Gen. Lee’s southern army pushed Union Maj. Gen. John Pope’s forces back into Washington and allowed Lee and his troops to cross the Potomac River into Union territory.

The deadliest one-day battle in American military history was ultimately a bloody stalemate, but the result favored the Union by showing the Federals’ ability to check Confederate advances into Union territory. It also was enough of a show of force by the North to keep Republicans in control of Congress and to embolden President Abraham Lincoln to issue the Emancipation Proclamation. A conclusive victory at Antietam would have influenced the congressional elections and encouraged Europe to recognize the Confederate States of America.

May 1864 was one of the bloodiest months in U.S. military history, with three major Civil War battles – each involving more than 100,000 engaged forces – taking place in northern Virginia and northwestern Georgia. One of these was the Battle of Spotsylvania Court House, part of Gen. Grant’s Overland Campaign to hunt down Gen. Lee’s forces. The 12-day engagement was inconclusive and costly, with the Union failing numerous times to break through Confederate lines.

Robert E. Lee’s greatest military victory would also be Confederate Lt. Gen. Thomas J. “Stonewall” Jackson’s last when he was killed by friendly fire during this battle. Lee made a daring decision to face off Maj. Gen. Joseph Hooker’s Army of the Potomac. But Hooker’s talk of creating a “perfect” plan to oust Lee from his encampment at Fredericksburg didn’t meet his leadership abilities. With half the number of engaged forces, Lee refused to retreat and his forces stood their ground, opening the way for a Confederate offensive into Pennsylvania and a showdown with the Union at Gettysburg two months later.

One of three major Civil War battles involving at least 100,000 engaged forces, the Battle of Resaca in northwestern Georgia – along an important transportation route of the Western & Atlantic Railroad – occurred at the same time as the Battle of Spotsylvania Court House,. Maj. Gen. William T. Sherman ordered his troops to attack Confederate-fortified bridges, after which Confederate Gen. Joseph E. Johnson was forced to order his troops to withdraw, giving the Federals important logistical access on their march toward Atlanta.