The Library of Congress is pleased to make the K Class - Law Classification - and all its subclasses available as linked data from LC's Linked Data Service, ID.LOC.GOV.  K Class joins the B, N, M, and Z Classes released in June 2012.  With about 2.2 million new resources added to ID.LOC.GOV, K Class is nearly eight times larger than the B, M, N, and Z Classes combined.  It is four times larger than LCSH.  If it is not the largest class, it is second only to the P Class (Literature) in the Library of Congress Classification system.

We have also taken the opportunity to re-compute and reload the B, M, N, and Z classes in response to a few reported errors.  Our gratitude to Caroline Arms for her work crawling through B, M, N, and Z and identifying a number of these issues.

The classification section of ID.LOC.GOV remains a beta offering.  More work is needed not only to add the additional classes to the system but also to continue to work out issues with the data.

We continue to encourage the submission of use cases describing how users would like to utilize the LCC data.


Please explore the K Class for yourself at

or all of the classes at


Contact Us about ID:
As always, your feedback is important and welcomed. Though we are interested in all forms of constructive commentary on all topics related to ID, we're particularly interested in how the data available from ID.LOC.GOV is used. Your contributions directly inform service enhancements.

You can send comments or report any problems to us via the ID feedback form or ID listserv (see the web site).

The LC Linked Data Service was first made available in May 2009 and offered the Library of Congress Subject Headings (LCSH), the Library's initial entry into the Linked Data environment. In part by assigning each vocabulary and each data value within it a unique resource identifier (URI), the service provides a means for machines to semantically access, use, and harvest authority and vocabulary data that adheres to W3C recommendations, such as Simple Knowledge Organization System (SKOS), and the more detailed vocabulary MADS/RDF. In this way, the LC Linked Data Service also makes government data publicly and freely available in the spirit of the Open Government directive. Although the primary goal of the service is to enable machine access to Library of Congress data, a web interface serves human users searching and browsing the vocabularies.  The new datasets join the term and code lists already available through the service:

* Library of Congress Subject Headings (LCSH)
* Library of Congress Children's Subject Headings
* Library of Congress Genre/Form Terms
* Library of Congress / NACO Name Authority File
* Thesaurus of Graphic Materials
* MARC Code List for Relators
* MARC Code List for Countries (which reference their equivalent ISO 3166 codes)
* MARC Code List for Geographic Areas
* MARC Code List for Languages (which have been cross referenced with ISO 639-1, 639-2, and 639-5, where appropriate)
* PREMIS vocabularies for Cryptographic Hash Functions, Preservation Events, and Preservation Level Roles

The above code lists also contain links with appropriate LCSH and LC/NAF headings.

LC's Linked Data Service is managed by the Network Development and MARC Standards Office of the Library of Congress.

Kevin Ford
Network Development and MARC Standards Office
Library of Congress
Washington, DC