After the war ended, the Union Army established the site as a national cemetery. Today, Andersonville National Historic Site serves as the final resting place for more than 20,000 U.S. military men and women representing nearly every American conflict. Among them are the prisoners memorialized in O’Dea’s drawing.

This weekend, the cemetery will hold a series of free Memorial Day events for the public. As part of the commemoration, volunteers will place small American flags on the veterans’ graves.

Memorial Day was formally established in the aftermath of the Civil War, America’s deadliest conflict, as people were still processing what happened at Andersonville.

A copy of O’Dea’s illustration remains on display inside Andersonville’s National Prisoner of War Museum, which doubles as the park’s visitor center. Gia Wagner, the historic site’s superintendent, is struck by how it grabs visitors’ attention.

“They are all captivated by it when they are here because it really does depict the scene of suffering that was happening,” she said. “It is still hard for me to believe that many people were within the prison site.”

Credit: HYOSUB SHIN / AJC

Credit: HYOSUB SHIN / AJC

O’Dea’s odyssey

Born in Ireland, O’Dea enlisted as a private with the 16th Maine Infantry Regiment in September 1863, his military records show. Then a teenager, O’Dea identified himself as a manufacturer of foot-shaped molds for forming and repairing shoes.

Originally designed to hold 10,000 prisoners, the camp quickly became overcrowded, holding more than 32,000 by August 1864. That overcrowding was driven in part by the suspension of prisoner exchanges.

In May 1863, according to the National Park Service, the Confederate government passed a resolution barring the exchange of captured Black Union soldiers. Two months later, President Abraham Lincoln issued an order effectively suspending the exchange system until the Confederates agreed to treat Black and white prisoners the same.

Lives were at stake. Captured Black Union troops and their white officers faced execution, according to the National Museum of the United States Army. In April 1864, for example, Confederates fatally shot Black Union soldiers who were captured at Fort Pillow in Tennessee.

Struggling mightily against the Union and experiencing deteriorating economic conditions, the Confederate government did not provide adequate food, shelter or medical care for its captives at Camp Sumter. Many died from scurvy, dysentery and exposure. They were buried shoulder to shoulder in shallow trenches.

During his captivity, O’Dea was chained to a post for two days under the sun as punishment for attempting to escape, he said during a deposition for his military pension benefits. He also testified he was beaten by a gang of prisoners after reporting one of the “raiders” had stolen a fellow detainee’s watch.

“I was thrown down, kicked and beaten ‘til I was unsensible,” he said in his deposition. “When I came to, I was not able to see for some two weeks.”

O’Dea wrote that he was also held in other Confederate prisons, including ones in Danville, Virginia, and Florence, South Carolina. His military records initially identified him as a deserter, but they were later corrected.

Nearly a year after he was captured, O’Dea was freed. A fellow soldier who saw O’Dea after he returned to his unit wrote in an affidavit that O’Dea was “so wasted in appearance that he was unfit for any duty.”

Honorably discharged, O’Dea settled in Cohoes, New York, where he worked as a mason, married and raised five children. Meanwhile, he suffered from chronic eye problems and heart disease because of “exposure and cruelty” he experienced during his captivity, his pension records show.

“I have used medicines enough to supply a drugstore,” O’Dea wrote in a letter to federal pension officials in 1888.

Credit: National Park Service

Credit: National Park Service

‘The annals of civilization and barbarism’

With only his memory guiding him, O’Dea began work on his drawing of Camp Sumter in the winter of 1879 and finished it in 1885, according to a pamphlet he wrote about his illustration.

One of his scenes portrays the prison’s cemetery, where, he wrote, “the dead were thrown promiscuously upon a wagon the same as cordwood.” Another scene depicts a guard shooting a prisoner collecting water near the “dead line,” the name given to the compound’s do-not-cross boundary.

A third image reveals the types of punishment prisoners faced, including being hanged by their thumbs. The illustration also features a portrait of the stockade’s Confederate commander, Capt. Henry Wirz, who was convicted of conspiracy and murder and hanged in Washington after the war.

“In all the annals of civilization and barbarism, there never was, and I doubt never will be, such another place as Andersonville,” O’Dea wrote. “No truer sentence ever passed the lips of man, than when this was called the ‘Hell Upon Earth.’”

In addition to memorializing those who died at Andersonville, O’Dea’s drawing validates the experiences of prisoners of war who might not have experienced much or any combat, said Damian Shiels, an author and historian who collected O’Dea’s military pension records.

“O’Dea effectively enlists, is in a camp, goes off and then, bang, you are in Andersonville Prison,” said Shiels, who is researching the experiences of Irish Americans who served in the Union Army. “His entire war is there.”

“It is the defining moment of a lot of men’s war and what they witnessed there. There is definitely a strong desire to memorialize their view of what happened and the people who died there.”

Some prisoners who were held at Andersonville, Shiels added, felt “they were utterly abandoned by the United States government while they were there.”

One of the images in O’Dea’s drawing features the scales of justice, a headstone for the “martyrs” who died at Camp Sumter and a book titled, “The Unwritten History of Andersonville Prison.” In his pamphlet, O’Dea highlighted the suspension of prisoner exchanges and wrote the soldiers who “played the most important part in the late war” had been forgotten.

“But the soldier has not forgotten,” O’Dea wrote. “The soldier gave up his home, his blood, his life, for his country.”

Credit: National Park Service

Credit: National Park Service

Credit: National Park Service

Credit: National Park Service

Credit: Natio

Credit: Natio

Memorial Day’s beginning

The same year he published his pamphlet, O’Dea ordered 10,000 lithograph copies of his drawing and sold each for $5, according to an article by Paul Perreault, then-town historian for Malta, New York. O’Dea offered a reduced rate to members of a powerful group of Union Army veterans called the Grand Army of the Republic.

Toward the end of the 19th century, people put copies on public display in various venues across the nation, attracting newspaper coverage. In 1888, for example, the Vincennes (Indiana) Commercial newspaper reported on a copy the local Grand Army of the Republic post exhibited in a show window.

“O’Dea’s piece speaks to that,” said Towle, who has collected 19th century newspaper articles about the drawing. “As you have this reconciliation happening, there still are soldiers who are really driving home the point that they don’t want to forget the realities of war while war is becoming romanticized by the general public.”

In January 1926, O’Dea’s pension records show, he was 80, widowed, nearly blind and experiencing heart troubles. His daughter Estella wrote that he was “not himself at times” and that he required attention at night when he “walks through the house for hours. Cannot be left alone at any time.”

He died two months later and is buried in St. Agnes Cemetery in Cohoes.

Credit: National Park Service

Credit: National Park Service