The Historical Society of Long Beach (HSLB) was formed in 1962 with the mission to collect, preserve, and present the city’s history. Throughout the years the HSLB has occupied many locations around the city, settling at its current location in Bixby Knolls in 2007. Operations are sustained at the HSLB by grant funding, membership dues, and community fundraising through programs and events.

Documents and photos relating to the history of the Crescenta Valley. The La Crescenta Valley Historical Society has a lot of materials on the New Years Flood of 1934, and the town of Montrose, plus some materials on the American portrait artist S. Seymour Thomas.

The Library has a large collection of manuscripts, printed books and periodicals, photographs, maps and ephemera relating to Los Angeles.

The June L. Mazer Lesbian Collection, formerly the West Coast Lesbian Collections, was founded in Oakland, California, in 1981. Six years later it was moved to Los Angeles by Connexxus Women's Center/Centro de Mujeres, and it acquired its present name in 1987 after the death of June L. Mazer, a community activist and an invaluable supporter of the collection.