In late 1861, U.S. officials selected Johnson's Island as the site for a prison camp to hold up to 2,500 captured Confederate officers.

The island offered easy access by ship for supplies to construct and maintain a prison and its population.

Sandusky Bay offered more protection from the elements than other nearby islands, which were also closer to Canada in case of a prison break.

More than 40 buildings stood outside the prison walls, including barns, stables, a limekiln, forts, barracks for officers, and a powder magazine.

The island housed officers, some of whom received money from home to purchase goods offered at the sutler's store, run by those who followed the army and sold supplies to the soldiers.

[9] After the unraveling of a Confederate espionage ring that had conspired to seize the Great Lakes warship USS Michigan and a mass breakout of prisoners, Forts Johnson and Hill were constructed over the winter of 1864–65.

On June 8, 1910, Moses Ezekiel's statue Southern (or the Lookout), a monument to the Confederate prisoners-of-war on the island, was unveiled.

In conjunction with Heidelberg University, the Friends have sponsored educational and research programming at this National Historic Landmark.