From The New York Times:
Founded in 1754, the New York Society Library, on East 79th Street in Manhattan, calls itself the oldest cultural institution in New York City.
“If you can find one that’s older, let us know,” said Carolyn Waters, its head librarian.
Yet the place remains little known, even to many New Yorkers.
Since this is a membership library supported by annual fees and its endowment, patrons must pay to enjoy lending privileges for its roughly 300,000 volumes on a broad array of subjects, including plenty of material about New York City.
The library has roughly 2,800 members, she said, and allows nonmembers to use its ground-floor reference room for browsing and reading, and to attend many of its talks, exhibitions and events.
See Also: New York Society Library Online Catalog