Library of Congress - Using The Library

Using The Library

The library is open to the general public for academic research and tourists. Only those who are issued a Reader Identification Card may enter the reading rooms and access the collection. The Reader Identification Card is available in the Madison building to persons who are at least 16 years of age upon presentation of a government issued picture identification (e.g. driver's license, state ID card or passport). However, only members of Congress, Supreme Court Justices, their staff, Library of Congress staff and certain other government officials may actually remove items from the library buildings. Members of the general public with Reader Identification Cards must use items from the library collection inside the reading rooms only; they are not allowed to remove library items from the reading rooms or the library buildings.

Since 1902, libraries in the United States have been able to request books and other items through interlibrary loan from the Library of Congress if these items are not readily available elsewhere. Through this, the Library of Congress has served as a "library of last resort", according to former Librarian of Congress Herbert Putnam. The Library of Congress lends books to other libraries with the stipulation that they be used only inside the borrowing library.

The Library of Congress is sometimes used as an unusual unit of measurement to represent an impressively large quantity of data when discussing digital storage or networking technologies.