Who Won the Battle of Gaines’ Mill?

With the Union and Confederate capital cities so close together, it seemed common sense for the Union to use its manpower and industrial advantage to take the quickest route to end the war: seize the Confederate capital of Richmond, Virginia. The Peninsula Campaign of 1862 was an attempt to take Richmond by brute force. Could the Confederacy hold out and protect its capital, or would it be overwhelmed?

The Battle of Gaines’ Mill was the most intense battle of the Seven Days Battles during the mid-1862 Peninsula Campaign conducted by Union General George McClellan against the Confederacy. McClellan, commanding the Army of the Potomac, was attempting to seize the Confederate capital city of Richmond, Virginia by straightforward assault. Unfortunately for McClellan, the Confederates were prepared for a staunch defense. On June 27, 1862, battle commenced (again), with Confederate general Robert E. Lee taking advantage of the fact that one-third of McClellan’s army—an outnumbered portion—was separated from the other two-thirds by the Chickahominy River.

Lee attacked, weighing his numerical advantage over the Union forces holding the high ground. For most of the day, Union troops under General Fitz John Porter held firm, but the late arrival of Confederate General Thomas J. “Stonewall” Jackson broke the stalemate. Together, Lee and Jackson orchestrated the largest Confederate frontal assault of the war—32,000 men—and swept the Union lines back toward the Chickahominy River. This decisive victory effectively ended McClellan’s Peninsula Campaign and saved Richmond…for almost three years.

Timeline of the Battle of Gaines’ Mill

For about a month, McClellan’s Army of the Potomac was successful, pushing back Confederate General Joseph E. Johnston’s army toward Richmond.

On May 20, McClellan was within fifteen miles of the Confederate capital city but paused for reinforcements after crossing the Chickahominy River.

On May 31, Johnston attacked, stalling the slow Union advance. Robert E. Lee was named the new Confederate commander of the Army of Northern Virginia, and he planned to confront McClellan.

On June 25, 1862, the Seven Days Battles began in earnest.

Two days later, the Battle of Gaines’ Mill, the largest of the series, commenced after McClellan had ordered his field commander, General Fitz John Porter, to re-center his forces on the mill’s high ground.

In the afternoon, the Confederates attacked after realizing they heavily outnumbered Porter’s Union forces. Several direct charges were made across open ground, resulting in heavy Confederate casualties.

A stalemate lasted for hours until the arrival of Confederate General Thomas J. “Stonewall” Jackson, whose men turned the tide.

By dusk, the remainder of Porter’s army that had not escaped across the Chickahominy River surrendered.

The Seven Days Battles, including its largest single engagement at Gaines’ Mill, was prompted by the new command of Confederate General Robert E. Lee. Given the charge of the Army of Northern Virginia on June 1, 1862, Lee set out to reverse McClellan’s advance on Richmond. In late June, Lee attacked, trying to dislodge McClellan. Although the first two days of battles were relatively inconclusive, causing only bloodshed rather than much tactical change, Lee realized on the third day that he had a numerical advantage against Union general Fitz John Porter.

Although Porter had a strong defensive position on the high ground at Gaines’ Mill, he was outnumbered, and reinforcement would be difficult due to his back being at the river. Thus, Lee was willing to undertake costly frontal assaults, which eventually succeeded with the help of “Stonewall” Jackson. Stakes were high, which also influenced Lee’s decision to attack: if McClellan was not pushed back, Richmond might be taken quickly, ending the war and the Confederacy. If Richmond could be seized before the Confederate government could evacuate, there would be little hope of maintaining the independence movement.

Why Was the Battle of Gaines’ Mill Significant?

The Battle of Gaines’ Mill was significant in that it effectively ended McClellan’s assault on Richmond. Although fighting in the Seven Days Battles would continue until July 1, Gaines’ Mill was the physical and psychological blow that broke McClellan’s offensive. Later, this could also be seen as dooming McClellan’s 1864 presidential campaign. Although McClellan would later defeat Lee’s first invasion of the North in the Battle of Antietam, his failure to pursue the retreating Army of Northern Virginia added to his failed Peninsula Campaign to sink his military career. Eventually, Ulysses S. Grant took command of the Army of the Potomac, captured Richmond, and became US president afterward.

A second piece of significance of the Battle of Gaines’ Mill was that it began the impressive run of Confederate General Robert E. Lee at the head of the Army of Northern Virginia. For a year after Gaines’ Mill, until his defeat at Gettysburg, Lee was on a hot streak. Victories at the Second Battle of Bull Run, Fredericksburg, and Chancellorsville all added to Lee’s reputation as a military genius. This led to Lee being revered in the South even after the Confederacy’s collapse in 1865.

1. Casualties

The fighting was some of the most intense of the war, with more than 15,000 casualties inflicted between six and nine hours of heavy fighting. Lee’s Confederates suffered higher casualties, almost 9,000, by having to cross open fields against defenders who held the high ground. However, by winning the battle, the Confederates took over 1,000 Union soldiers prisoner by the Chickahominy River.

2. Commanders

Union forces were led by Army of the Potomac commander George McClellan and, in the field, by General Fitz John Porter. Like most generals in the war, Porter was a West Point graduate and veteran of the Mexican-American War. Although Porter was praised for his tenacity at Gaines’ Mill, he was condemned a few months later after the Union defeat at the Second Battle of Bull Run (Second Manassas). Unlike most generals defeated in battle, who were transferred to less rigorous roles, Porter was court-martialed and removed from the Army entirely.

Confederate forces were led by Army of Northern Virginia commander Robert E. Lee and his compatriot, Thomas J. “Stonewall” Jackson. Both men, like Porter, were West Point graduates who served in Mexico. Lee and Jackson were also Virginians and highly motivated to defend their home state. Jackson won acclaim for his actions during the Seven Days Battles but did not survive the Civil War: he died after being wounded by friendly fire in the Battle of Chancellorsville in 1863.

3. Number of Forces Involved

Fitz John Porter had about 34,000 men under his command, representing about one-third of the Union forces in the campaign at the time. Arrayed against him were about 60,000 Confederate soldiers, putting the total number of men-at-arms at Gaines’ Mill at around 94,000. In addition to losing about a thousand soldiers who were taken prisoner, Porter also suffered the loss of many artillery pieces.

Today, the battlefield can be visited as part of the Richmond National Battlefield Park, which is about ten miles northeast of Richmond, Virginia. However, parts of the battlefield are privately owned today, so visitors should be mindful of signs and property lines. Walking trails provide visitors with self-guided tours. Due to the many battles fought nearby, visitors to the Richmond National Battlefield Park can learn about several Civil War engagements! Those who spend time in the city of Richmond can also enjoy historic sites that date back to the colonial era.

5. Trivia: Most Decisive of the Seven Days Battles

Of the Seven Days Battles, Gaines’ Mill is considered the only decisive victory of either side. However, since it belonged to the Confederacy, it represents an overall victory for the Confederacy in the Seven Days Battles and the Peninsula Campaign as a whole. McClellan retreated from the Virginia Peninsula, and Richmond remained untaken for almost another three years. The Confederate victory also began the run of success enjoyed by Robert E. Lee, thwarted only at Gettysburg in July 1863.

Aftermath of Gaines’ Mill: Richmond Stands Strong

Lee’s victory at Gaines’ Mill broke McClellan’s offensive and saved the city of Richmond from being captured. This victory had an oversized effect on the perception of the Civil War as a whole, as both Northern civilians and foreign observers focused mostly on news from the Eastern Theater in Virginia. Despite Union victories in the Western Theater during the spring and summer of 1862, including the seizure of New Orleans and Baton Rouge in Louisiana, many observers felt that the Confederacy was winning the war due to its ability to repel invaders from Richmond.

Although McClellan did not suffer a catastrophic loss at Gaines’ Mill, he was humiliated and blamed the administration in Washington DC for not providing enough support. Due to the failure of the Peninsula Campaign, McClellan was effectively replaced by General John Pope. Although McClellan kept his command, a new Army of Virginia was created for Pope. Unfortunately for Pope, his defeat at the Second Battle of Bull Run saw power return to McClellan as the Army of Virginia was folded in September 1862. McClellan went on to win the Battle of Antietam days later but was criticized for failing to pursue Lee’s retreating army and striking a solid blow.