In 1965, Mayoral candidate, John Lindsay saw a need to spruce up the city a bit. He suggested that New York City create “vest pocket parks” or “adventure playgrounds.” Later, when he was elected Mayor of New York City, he implemented his ideas and helped created the first vest pocket parks in the city. According to an essay on the New York City Department of Parks and Recreation, Park Commissioner, Thomas P.F. Hoving encouragee their use for public events aided him by bring various events to the parks. He even banned cars in Central Park on Sundays. In 1967, the city completed 10 vest pocket parks in vacant city lots equal to or smaller than one-quarter acre.
The very first pocket park was created at 65 W. 128th by Reverend Linnette C. Williamson of Christ Community Church of Harlem. She was instrumental in developing this pocket park and it was later dedicated in her honor.
Here is one I discovered near 6th Ave. It is right outside an apartment building on 29th St.