New York has a surprising number of abandoned islands. We've previously featured Hart Island, which over the years has served as a cemetery, workhouse and asylum. An equally fascinating example is North Brother Island, which lies in the East River, between the Bronx and Riker's Island. In the late nineteenth century, a hospital, the Riverside, was built on the island to house people suffering from contagious diseases. The most famous resident was Mary Mallon, known as "Typhoid Mary", who was a carrier of typhoid and infected many people with the disease, though she herself never showed any symptoms. Mallon was held on the island against her will for more than two decades.
The island is also the site of the largest loss of life in New York's history, prior to the terrorist attacks of 2001. In 1905, the General Slocum, a steamship, caught fire and sank nearby. Almost 1,000 people were killed in the accident, though more than 300 were rescued.
After the Second World War, veterans were housed on North Brother; later it became a treatment centre for heroin addicts. However, since 1963 the island has been abandoned, and is now a strictly protected bird sanctuary for rare black-crowned night herons.
You can read an article outlining the history of the island here, along with some historical photographs. There are also two sites with excellent photographs of North Brother in its current abandoned state. You can view the first by clicking here, and the second by clicking on the image below.