The largest library in the world is the U.S. Library of Congress in Washington, D.C.

The British Library the world's other great library houses a collection comprising of 150 million items as against the 130 million housed by the Library of Congress.
However in terms of shelf space the Library of Congress shelves occupy a space of about 850 km (530 miles) while the British Library shelf space is 625 km (388 miles) long. The Library of Congress' collection of books is in the range of 29 million while the number of books of the British Library is about 25 million.

The Library of Congress was established in April 1800 and is spread over three buildings namely The Thomas Jefferson Building, The John Adams Building and The James Madison Memorial Building; the collection of the library consists of along with books, newspapers from across the world, microfilm reels (500,000), comic books (6000), manuscripts (58 million), films, maps (4.8 million) and sound recordings (2.7 million); the rarest item in the library is a Gutenberg Bible dating from the 15th century.