The Library of Congress > Linked Data Service > About: Main


The Library of Congress Linked Data Service ( provides interactive and machine access to the Library's authority and bibliographic metadata, along with commonly-found standards and vocabularies used and/or maintained by the Library of Congress. Each controlled vocabulary list has a resolvable URI, as does each data value within it. Ontologies for several major data element sets are also available.

URIs accessible at link to bibliographic descriptions and controlled vocabularies and the values within them. This data service does not provide access to the physical or electronic holdings of the Library. To request or access the Library's holdings, please visit the catalog.

The databases, ontologies, authorities, and vocabularies currently included in this service are listed on the home page. The Library of Congress will continue to release additional vocabularies as needed, including those that support BIBFRAME, MARC, METS, MODS, PREMIS, and other standards.

The Linked Data Service provides a web interface with search capability for individual vocabulary values. It supports instant download of the metadata for the value with a choice of serializations. Options include common RDF serializations (RDF/XML, JSON, N-Triples) employing Simple Knowledge Organization System (SKOS) and other ontologies. It also offers bulk downloads. See the Technical Center for more details.

Concepts within Library of Congress Linked Data Service assert relationships to similar concepts found in non-Library of Congress data whenever they are known. These assertions are made through linking via URIs to concepts found on the World Wide Web that are maintained outside of the Library of Congress. Because the target URIs are hosted by another institution, the Library of Congress cannot guarantee that these links will resolve successfully.

The Library of Congress has prepared this linked data system and is making it available as a public domain data set. While it has attempted to minimize inaccuracies and defects in the data and services furnished, THE LIBRARY OF CONGRESS IS PROVIDING THIS DATA AND THESE SERVICES "AS IS" AND DISCLAIMS ANY AND ALL WARRANTIES, WHETHER EXPRESS OR IMPLIED.