[1] The islands had long been privately owned, but were purchased by the federal government in 2007 with some funding from the Trust for Public Land and others; both were given to the city.

[5] Public access is prohibited but permission is occasionally given to researchers and journalists; a NYC Parks staff member escorts all such visitors.

After the nationwide housing shortage abated, the island was again abandoned until the 1950s, when a center opened to treat adolescent drug addicts.

[14] The facility is said to have been the inspiration for the Broadway play Does a Tiger Wear a Necktie?, which helped to launch the career of Al Pacino.

John Lindsay, for instance, proposed to sell it, and Ed Koch thought it could be converted into housing for the homeless.

Most of the original 25 buildings still stand, "in various states of extreme dilapidation"; hence, permits to visit are issued only for "compelling academic and scientific purposes".

In October 2014, New York City Council member Mark Levine, chair of the City Council's Parks Committee, led a delegation to visit the island,[22] and declared his desire afterward to open the island for limited "light-touch, environmentally sensitive" public access.

[14] In 2016, the executive director of the Historic House Trust warned that there were many hazards, due to the deteriorating buildings and open manholes.

However, the island is only about a half-mile from the Bronx and the country estates of the city's rich, such as William Ligett and Jacob Lorillard, both scions of tobacco families.

[26] Jacob Ruppert, a brewery magnate and early owner of the New York Yankees, had a summer house on the island that burned down in 1909.

Ruppert owned the island until the late 1930s, and in 1944 it was purchased by John Gerosa, president of the Metropolitan Roofing Supply Company; he said he planned to construct cottages for employees but they were never built.

The Trust for Public Land then acquired the island on behalf of those organizations, and then donated it to the city's Parks Department as a wildlife sanctuary.

[14][1] From the 1980s through the early 2000s, North Brother Island supported one of the area's largest nesting colonies of black-crowned night heron.

[32] In June 2009, North Brother Island was featured in episode 8 ("Armed and Defenseless") of Life After People on the History Channel.

North Brother Island was also mentioned as the Enclave base in Moon Girl and Devil Dinosaur's season 1 finale "O.M.G.