List of largest libraries in the United States

The largest libraries in the United States is determined by the number of volumes or titles held, by circulation, including library materials checked out or renewed, or by number of library visits. As of 2018, the largest public library in the United States and largest library in the world is the Library of Congress in Washington, D.C., the de facto national library of the United States, which holds over 167 million items, including over 39 million books and other printed materials, 3.6 million recordings, 14.8 million photographs, 5.5 million maps, 8.1 million pieces of sheet music, and 72 million manuscripts.

Source: Wikipedia — List of largest libraries in the United States (CC BY-SA 4.0)