Research Center Main Reading Room

About this Reading Room

The Main Reading Room is one of the principal reference and book service points for the Library's general collections. Located in room LJ 100 on the first floor of the Thomas Jefferson Building, the Main Reading Room is the perfect place to get started on your research at the Library of Congress. Reference librarians are available for research consultations to help guide you.

The home to history, humanities, social sciences, and genealogy, the beautiful Main Reading Room is the largest public reading room in the Library. The general collections include books, pamphlets, and bound (non-current) periodicals. Our reference collections contain approximately 50,000 volumes, city directories, and family histories. It’s also connected to the MERC in LJ 139, where you can access microfilm and electronic resource collections and use computer workstations for searching the Library’s online catalog, online subscription resources like databases and journals, and accessing STACKS. Reader Registration is also located here.

Ask a Librarian at the Library of Congress

Appointments are not required, but encouraged. To help us better serve you, request a Main Reading Room research appointment to ensure collection material is accessible during your visit at the Library. We encourage you to review the Library’s Know Before You Go information to prepare you for your visit. For additional instructions on scheduling an optional appointment, see details on our Research Appointments page.


Library of Congress
10 First Street, SE
Thomas Jefferson Building, LJ 100
Washington, DC 20540-4810


Public Hours
Monday through Thursday 8:30 a.m. - 8:30 p.m.
Friday, Saturday 8:30am - 5:00pm
Closed Sundays & Federal Holidays
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