As John Wilkes Booth stepped into President Lincoln’s booth at Ford’s Theater on the evening of April 14, 1865, Union prisoners of war were heading home on foot and by rail, free from Andersonville, Cahaba and other prisons. Several thousand men had been brought to a transit camp at Vicksburg, Miss., where they awaited transport along the Mississippi River.

Eleven days later, 2,100 of those soldiers, many sick, many barefoot, boarded the wooden side-wheeler steamboat Sultana. The ship was built to carry 375 passengers; that day it steamed north with 2,427, including civilian men, women and children along with the soldiers.

At 2 a.m., when the ship was just seven miles upriver from Memphis, three of its four boilers exploded. Nearly 1,800 people, mostly Union soldiers, died in what remains the worst maritime disaster in American history – worse, even, than the Titanic – and one of the largest military losses of life in a single day.

Those who were not killed outright by the explosion died in the crush to abandon the ship, or drowned in the river below. The water was still chilly with winter runoff, and many of those who made it into the water died of hypothermia. One survivor, Daniel Allen, testified in 1892: 

I pressed toward the bow, passing many wounded sufferers, who piteously begged to be thrown overboard. I saw men, while attempting to escape, pitch down through the hatchway that was full of blue curling flames, or rush wildly from the vessel to death and destruction in the turbid waters below. I clambered upon the hurricane deck and with calmness and self-possession assisted others to escape.” ...