Every soldier fears dying in combat. But in the Civil War, being taken prisoner was nearly as life-threatening, with contagious illnesses spreading like wildfire in unsanitary prison camps. 

How many prisoners died in Civil War stockades may never be known for sure, but it’s estimated that of the 400,000 soldiers taken prisoner in Northern and Southern prisons between 1861 and 1865, 56,000 died. Of that number, about 26,000 died in Union custody. (The Civil War was one of the wars that killed the most Americans.)

With little knowledge of how diseases spread and fewer tools to combat the ailments, doctors could do little to help the prisoners. Contagious ailments such as typhoid, measles, and dysentery infected prisoners at a high rate, leading to what would now in many cases be preventable deaths.

To compile a list of the most common causes of death in Union prisoners of war camps during the Civil War, 24/7 Tempo reviewed reports by consumer data site Statista, which drew on Library of Congress and Oxford University Press information about Union prisons during the American Civil War from 1861 to 1865.

Click here to see the ways Civil War soldiers died in Union prison camps

Early in the war, Confederate and Union armies swapped prisoners in equal numbers and of equivalent rank. Yet the exchanges were contentious from the start, as both sides argued over the exact numbers. When Black soldiers joined the Union troops, Confederate commanders refused to exchange Black soldiers for white combatants.  

In 1864, Union General Ulysses S. Grant halted the prisoner exchanges as he and the Union believed Confederate soldiers would return to the battlefield and prolong the war. Consequently, prison camps teamed with prisoners who perished in great numbers as disease took a ghastly toll. That contributed to the fact that the conflict was No. 1 on the list of 12 wars where the most Americans died outside of combat.

To compile a list of the most common causes of death in prisoners of war camps during the Civil War, 24/7 Tempo reviewed reports by consumer data site Statista, using Library of Congress and Oxford University Press information about Union and Confederate prisons during the American Civil War from 1861 to 1865.