The Houston Public Library serves more than 2.1 million people in the city of Houston. The library has 44 public service units, maintains over 2.6 million volumes, and circulates more than 7.1 million items per year. The library is rich in history collections, with materials covering Houston history, African American history, Hispanic history, and genealogy. Residents can also utilize the library's passport services to apply for a U.S passport at any of its five locations.