On a remote island fortress surrounded by turquoise waters, one of the most infamous prisoners of the Civil War era found himself fighting not for escape—but for the lives of his fellow inmates.
Dr. Samuel Mudd, sentenced to life for aiding Lincoln’s assassin, would face a yellow fever epidemic in 1867 that turned a Union military prison into a scene of desperation. His actions inside Fort Jefferson reshaped the final years of his confinement.
A Prisoner Sent to the Edge of America
After being convicted in July 1865 for conspiracy in Abraham Lincoln’s assassination, Mudd was transported with three others to Fort Jefferson, 70 miles west of Key West.
The island fortress, originally built to defend against Caribbean pirates, had been converted into a military prison during the Civil War. When Mudd attempted to escape that September, he was punished with a stint in a dungeon cell. He later shared a room with his fellow conspirators and endured a grueling climate, swarms of insects, and spoiled food.
The Fever Takes Hold
On August 18, 1867, yellow fever cases began appearing in the garrison. By early September, the fort’s doctor, Joseph Sim Smith, succumbed to the disease. Hundreds of soldiers, prisoners, and officers were trapped on the island. With no one else left to provide care, Mudd volunteered to take over.
Despite his bitterness toward the government that imprisoned him, Mudd worked continuously, implementing hygiene measures like clean bedding and isolation. He treated patients with calomel, Dover’s Powder, and warm teas.
Death Toll and Response
Of the 270 who contracted yellow fever at Fort Jefferson, only 38 died—14 percent. That was far lower than other 19th-century epidemics. Lieutenant Edmund Zalinski, a survivor, credited Mudd’s care and petitioned President Andrew Johnson for his release.
Nearly 300 others signed the document. Mudd’s wife, Sarah, personally lobbied Johnson, and in January 1869, a delegation from Maryland met with him. Johnson issued Mudd a pardon on February 8, 1869.
A Return Home
On March 11, Mudd left Fort Jefferson aboard the steamer Liberty. He was 35 but appeared much older. His fellow prisoners, Samuel Arnold and Edman Spangler, were released soon after. Mudd returned to Maryland and resumed life with his family.
At Fort Jefferson, the dungeon where he once slept still bears a plaque acknowledging his efforts during the epidemic. It reads that he “earned the admiration and gratitude of all who observed or experienced his generous and faithful service to humanity.”
Dr. Samuel Mudd treated John Wilkes Booth’s broken leg hours after Lincoln's assassination.
Though he claimed innocence, his earlier meetings with Booth led to a conviction for conspiracy and a life sentence at Fort Jefferson in the Gulf of Mexico…🧵👇 pic.twitter.com/v9ynO9VyHP
— Detective Tiger's Stories (@TigerDetective) June 29, 2025