The Detroit Public Library (DPL) is the largest library system in the U.S. state of Michigan by volumes held (after the University of Michigan Library) and is the 20th largest library system (and the fourth-largest public library system) in the United States. It is composed of the Main Library on Woodward Avenue, which houses DPL administration offices, and 23 branch locations across the city. The Main Library is part of Detroit's Cultural Center Historic District listed in the National Register of Historic Places adjacent to Wayne State University campus and across from the Detroit Institute of Arts.