The North Brother Island is a small island in the East River of New York City, just a short distance from the Bronx. It is now an uninhabited bird sanctuary but between 1885 and the late 1930's it was were patients of the Riverside Hospital were kept in isolation.
The Riverside Hospital, built first as a smallpox hospital but later expanded to other quarantinable diseases, moved to the North Brother Island in 1885. Among its most famous patients was "Typhoid Mary", the first person in the United States who carried and transmitted typhoid fever. She lived in the island for more than two decades until she died in 1938. The hospital closed down shortly thereafter.
Today the island is abandoned and off-limits to the public. The buildings of the Riverside Hospital have been taken over by vegetation and are in danger of collapse.