North Brother Island is a small uninhabited island in the East River between the Bronx and Rikers Island, best known as the site of Riverside Hospital, a quarantine facility where Typhoid Mary — Mary Mallon, the first person in the United States identified as an asymptomatic carrier of typhoid fever — was forcibly confined for the last 23 years of her life until her death in 1938. The island was later used as a drug rehabilitation center before being abandoned in 1963, and is now a restricted wildlife refuge managed by the city, its crumbling hospital ruins overtaken by vegetation and nesting herons.