Backed by Samuel J. Tilden, the Astor Library and the Lenox Library agreed to merge and form the New York Public Library.

Samuel Jones Tilden was an American politician who served as the 25th governor of New York and was the Democratic nominee in the disputed 1876 United States presidential election.

The Astor Library was a free public library in the East Village, Manhattan, developed primarily through the collaboration of New York City merchant John Jacob Astor and New England educator and bibliographer Joseph Cogswell and designed by Alexander Saeltzer. It was primarily meant as a research library, and its books did not circulate. It opened to the public in 1854, and in 1895 consolidated with the Lenox Library and the Tilden Foundation to become the New York Public Library (NYPL). During this time, its building was expanded twice, in 1859, and 1881.

The Lenox Library was a library incorporated and endowed in 1870. It was both an architectural and intellectual landmark in Gilded Age–era New York City. It was founded by bibliophile and philanthropist James Lenox, and located on Fifth Avenue between 70th and 71st Streets on the Upper East Side of Manhattan. Renowned architect Richard Morris Hunt designed the building, which was considered one of the city's most notable buildings until its destruction in 1912.

The New York Public Library (NYPL) is a public library system in New York City. With nearly 53 million items and 92 locations, the New York Public Library is the second-largest public library in the United States behind the Library of Congress and one of the largest public libraries in the world. It is a private, non-governmental, independently managed, nonprofit corporation operating with both private and public financing.