What is the biggest library in US?
List of the largest libraries in the United States
Library of Congress
The largest public library in the United States—and the largest library in the world—is the Library of Congress in Washington, D.C., which is the de facto national library of the United States.[2] It holds more than 167 million items, including "more than 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."[3] Other than the Library of Congress, the largest public library in the United States is the New York Public Library, while the largest research library in the United States is the Harvard Library.