The Buffalo & Erie County Public Library is located on Lafayette Square, Buffalo, New York, United States. The current facility, designed by James William Kideney & Associates and built in 1964, replaced the original Cyrus Eidlitz Buffalo Public Library Building dedicated in February 1887. The first Buffalo Public Library, in turn, replaced the Erie County, New York courthouse, which occupied the parcel from 1816 to 1876.

Founded ca. 1835 as the Young Men's Association (not to be confused with YMCA), prominent members included Mark Twain, who was the editor of the Buffalo Express from 1869 to 1871. The Young Men's Association was a private subscription library, meaning that paid membership was required in order to borrow books. In 1883, the Association began a fund-raising campaign for a new building and held an architectural competition, which culminated in Eidlitz's 1887 design. Upon completion, the Association turned over its collections to the citizens of Buffalo and the Buffalo Public Library was born, with no requirement for dues or membership.

Director from 1897 to 1906 was Henry Livingston Elmendorf, former secretary of the American Library Association (ALA) and husband of Theresa Elmendorf, who went on to serve as the ALA's first woman president. Director from 1906 to 1931 was Walter Lewis Brown, president of the American Library Association from 1916 to 1917.

Significant library collections include the original, hand-written manuscript of Twain's Adventures of Huckleberry Finn, which Twain donated to the library in 1885; and the Milestones of Science, a collection of first editions announcing major advancements in Western science.

The Institutional Services Division provides library services in three Erie County institutions.

Home Branch Library: Begun in 1956 with only a few books, this library at the Erie County Home has evolved dramatically. Users can now enjoy typical branch services as well as use the program room for coffee hour, old-time radio programs, read-alouds and travel club programs. Magnifying bars, book supports, tape-players, slides, slideviewers and electronic magnifiers are available for those needing special accommodations. Collections such as large print, video and audio cassettes create a warm place to find information or just sit and talk to a friend. For those unable to come to this library, room-to-room cart service to residents is provided.

Correctional Facility Library: This library located within the Erie County Correctional Facility contains both a law library and a general public library. Constructed in 1986, this 7,500-square-foot (700 m²) library was the first to be built as a core or focal point of a Correctional Facility. Its general collection contains over 8,000 books for inmates' educational and recreational purposes, and 1,000 square feet (93 m²) of the library is set aside to house a legal collection of over 4,000 volumes. Computers are available to inmates for their legal work.

Holding Center Library: Begun in 1969 as cart service to cells, this library has grown to encompass a new facility with both a legal collection and a general library. Residents can borrow all types of materials from adventure fiction to religious non-fiction and use a large legal collection while awaiting trial.