One of the oldest branch libraries in New York, the Aguilar Library was founded in 1886 and is named after Grace Aguilar.

When it became part of The New York Public Library, Aguilar was serving large Jewish and Italian immigrant populations. After World War II, an influx of Puerto Rican and other Spanish-speaking newcomers led to the creation at the branch of an extensive collection of materials in Spanish.

Designed by architects Herts and Tallant, 'Aguilar' is one of 65 city libraries built with funds donated by Andrew Carnegie. The interior of the building features a graceful hanging gallery with a cast-iron railing and a pressed-glass floor. 'Aguilar'  was renovated in 1996 as part of the Library's Adopt-A-Branch program and is fully accessible to persons using wheelchairs. The branch has a Language Learning Center for adults, a computer lab that provides instruction in English for speakers of other languages.