The Dag Hammarskjöld Library is a library on the grounds of the headquarters of the United Nations, located in the Turtle Bay/East Midtown neighborhood of Manhattan in New York City. It is connected to the Secretariat and Conference buildings through ground level and underground corridors. It is named after Dag Hammarskjöld, the second secretary-general of the United Nations. The library was founded in 1946, and the current library building was completed in 1961.
The library provides research and reference services to staff of the UN Secretariat as well as members of UN permanent missions. Additionally, the library is the main depository for United Nations documents and publications and maintains a selected collection of materials of the specialized agencies and United Nations affiliated bodies, as well as a collection of books, periodicals and other materials related to the organization's programs of activities. The library also produces a digital library of UN materials, an index to the proceedings and documentation of the major UN bodies, as well as providing research guides for finding UN-related material and information. The library also supports the network of UN libraries throughout the world by supporting collaborative information resource purchasing.