John O'Dea

He Volunteered to Charge Vicksburg’s Deadliest Defenses

John O'Dea was born in 1839 in Limerick, Ireland. Like many Irish immigrants of his generation, he eventually made his way to the United States, where the outbreak of the American Civil War drew him into Union military service. He enlisted in the U.S. Army and became a private in Company D of the 8th Missouri Infantry.

The 8th Missouri Infantry served in some of the most important campaigns of the Western Theater. By 1863, the regiment was part of the Union force operating against Vicksburg, Mississippi, one of the Confederacy’s most important strongholds on the Mississippi River.

Vicksburg stood on commanding ground above the river and was protected by a powerful system of earthworks, artillery positions, rifle pits, and fortified approaches. Capturing the city was essential to Union strategy. If Vicksburg fell, the United States could secure control of the Mississippi River and effectively divide the Confederacy.

Major General Ulysses S. Grant’s army reached the defenses of Vicksburg in May 1863 after a series of successful movements and battles in Mississippi. Grant initially attempted to break the Confederate position by direct assault.

The first major attack failed.

On May 22, 1863, the Union Army prepared for another large-scale assault. Before the main attack moved forward, a group of soldiers was called upon to perform an exceptionally dangerous assignment.

They became known as the volunteer storming party.

These men were expected to advance at the front of the assault toward the Confederate defenses. Their task placed them directly in the path of enemy rifle and artillery fire before the larger attacking formations could close on the fortifications.

John O'Dea volunteered.

As a private in the 8th Missouri Infantry, he joined the storming party and went forward during the assault on May 22.

The attack carried the volunteers across exposed ground toward heavily defended Confederate works. The men had little protection as they approached positions specifically constructed to repel frontal attacks. Confederate soldiers fired from cover while artillery swept the approaches.

O'Dea continued forward with the storming party.

His official Medal of Honor citation later recognized his “gallantry in the charge of the volunteer storming party.”

The citation is brief, but the circumstances reveal the danger behind those words. The men who volunteered knew they would be among the first soldiers exposed to concentrated Confederate fire. Their mission required them to move toward fortified positions before the main body of Union troops could reach the defenses.

The assault did not succeed in breaking the Confederate line.

Union troops suffered heavily, and Grant soon abandoned further attempts to capture Vicksburg through frontal attacks. Instead, he ordered the army to begin a formal siege.

For O'Dea, the failed assault had already produced the defining moment of his military service.

Historical accounts of the 8th Missouri Infantry indicate that he was wounded during the attack and suffered lasting damage to his hearing. He nevertheless survived the battle and the wider campaign.

The siege of Vicksburg continued for several weeks.

Cut off from supplies and under constant pressure, the Confederate garrison eventually surrendered on July 4, 1863. The fall of Vicksburg became one of the most important Union victories of the entire Civil War. Combined with Union success elsewhere along the river, it gave the United States effective control of the Mississippi and severed a major geographical connection between the eastern and western portions of the Confederacy.

O'Dea’s role in that victory was tied to the desperate assault that preceded the siege.

He remained an enlisted soldier, and there is no verified evidence that he rose above the rank of private. His eventual Medal of Honor therefore honored the courage of a soldier serving directly in the ranks.

Recognition did not come immediately.

More than thirty years after the assault on Vicksburg, the United States formally recognized what O'Dea had done.

On July 12, 1894, John O'Dea was awarded the Medal of Honor for his gallantry during the charge of the volunteer storming party on May 22, 1863.

The decoration linked his name permanently with one of the most dangerous episodes of the Vicksburg Campaign.

The Medal of Honor itself had been created during the Civil War and became the nation’s highest military decoration. Many Civil War recipients were recognized years or even decades after the actions for which they were honored, as wartime records were reviewed and acts of exceptional courage were brought forward for official recognition.

For O'Dea, the award preserved one moment above all others: the decision to volunteer for a mission that placed him at the front of a direct attack against fortified enemy positions.

His later civilian life is less extensively documented than his wartime service, but he lived for more than forty years after the end of the Civil War. In his final years, O'Dea resided at the Illinois Soldiers and Sailors Home in Quincy, Illinois, an institution created to care for aging veterans.

John O'Dea died in Quincy on July 2, 1905.

He was buried at Sunset Cemetery at the Illinois Veterans Home in Quincy.

By the time of his death, more than four decades had passed since the assault at Vicksburg. Yet the event that defined his military legacy remained clear.

On May 22, 1863, when Union commanders called for volunteers to move first against some of the strongest Confederate defenses surrounding Vicksburg, Private John O'Dea stepped forward.

He joined the storming party, advanced into the fire, and survived one of the most dangerous assaults of the campaign.

Thirty-one years later, the Medal of Honor ensured that his gallantry in that charge would not be forgotten.