September 1, 2021 Library of Congress Releases Data for Free Download and Discovery

Press Contact: Leah Knobel,
Public Contact: Deirdre Scott,

The Library of Congress announced today its third release of records in its online catalog for free bulk download for research and discovery. The release supports the Library’s effort to continuously expand open access to its vast collections.

This MARC (Machine Readable Cataloging Records) release surpasses previous releases and adds more than 200,000 new records to the existing 25 million record database.

Releases of MARC data uniquely exhibit the Library’s mission. They enable researchers to engage with the unparalleled and rich source metadata at the Library, inspire discovery of Library collections and provide resources to inform future discovery within the Library and data communities.

The data covers a wide range of Library items including books, serials, computer files, manuscripts, cartographic materials, music, sound recordings and visual materials.  Each record provides standardized information about an item, including its title, author, publication date, subject(s), genre, related names, summary and other notes.

The unabridged records are easily accessible through the Library’s Selected Datasets Collection in XML and UTF8 formats. Direct access to each data set is available here.

Staff from the Library’s Digital Strategy, Digital Content Management, and Cataloging Distribution Service collaborated on this data release. The records are the gold-standard for bibliographic data and a treasure trove of information that can be used far beyond cataloging. Previous releases have been used by data analysts, developers, statisticians and social scientists for study, collaboration and experimentation, including programs coordinated through LC Labs.   

The Library of Congress is the world’s largest library, offering access to the creative record of the United States — and extensive materials from around the world. It is the main research arm of the U.S. Congress and the home of the U.S. Copyright Office. Explore collections, reference services and other programs and plan a visit at; access the official site for U.S. federal legislative information at; and register creative works of authorship at


PR 21-047
ISSN 0731-3527