In June 1863, the Confederate Army needed somewhere to hold its growing number of Union prisoners. They chose Cahaba, a fading former state capital at the confluence of the Alabama and Cahaba Rivers in Dallas County. A large brick cotton warehouse built in 1860 on Arch Street, above the banks of the Alabama River, became the prison's core. Confederate soldiers erected a stockade around the warehouse and the surrounding grounds. The location was strategic -- close enough to Selma for supply and reinforcement, accessible by river, and far from the front lines. The commanding officer was Captain H. A. M. Henderson, a Methodist minister whose faith apparently informed his approach to the prisoners in his charge.

Cahaba Prison earned a distinction unusual for Civil War camps: one of the lowest death rates on either side of the conflict. Captain Henderson's humane treatment of his prisoners accounted for much of this. But conditions were far from comfortable. The prison surgeon, R. H. Whitfield, reported unsanitary conditions throughout the camp, citing contaminated water as the most serious threat. The warehouse was never designed to hold hundreds of men. Overcrowding was chronic, ventilation poor, rations thin. The prisoners endured, sustained partly by the knowledge that conditions at places like Andersonville in Georgia were incomparably worse. At Cahaba, men suffered but they lived -- a low bar that nonetheless separated Castle Morgan from the war's most infamous death camps.

Jacob Rush of the 3rd Ohio Cavalry arrived at Cahaba Prison on October 13, 1864. He had enlisted at fifteen, having lied about his age, and was captured as a spy -- an encounter that brought him face to face with General Nathan Bedford Forrest before his transfer to the prison. Inside the stockade, Rush met Union Captain Hanchette, and together they organized an escape attempt. The prisoners managed to overpower their guards, but the plan collapsed when the demoralized inmates could not follow through. Confederate reinforcements arrived from the town, and the conspirators were charged. Hanchette refused to identify the other plotters; no prisoner gave up a name. The suspected men were kept four days without food. Later, when Hanchette was supposedly being transferred for a prisoner exchange, he was shot dead on the road to Selma -- killed, Rush believed, on orders from Colonel Jones, who feared what the captain might reveal.

The prison was evacuated in March 1865 as the war ground toward its end. The surviving Union prisoners were marched to Vicksburg, Mississippi, for exchange. What should have been the journey home became a death sentence. The men were loaded onto the Sultana, a commercial side-wheel steamboat with a legal capacity of 376 passengers. More than 2,000 soldiers crowded aboard. On April 27, 1865, just north of Memphis, Tennessee, the Sultana's overstrained boilers exploded, tearing the vessel apart and igniting an uncontrollable fire. Over 1,100 people died -- the deadliest maritime disaster in United States history. Many of the dead were former Cahaba prisoners who had survived years of captivity only to perish on the river that was supposed to carry them home.

Nothing remains of Castle Morgan today. The cotton warehouse, the stockade, the grounds where prisoners paced and plotted -- all have vanished into the landscape at the river confluence. Cahaba itself became a ghost town after the county seat moved to Selma in 1866. The site is now part of Old Cahawba Archaeological Park, where interpretive markers note the prison's location. Jesse Hawes, a Union soldier of the 9th Illinois Cavalry who was held at Cahaba, published his account in 1888 as "Cahaba: A Story of Captive Boys in Blue." Jacob Rush also wrote of his experience. Their words are what survive -- testimony from men who walked out of a prison and into a disaster, recorded so the story would not disappear as completely as the buildings that held them.