NUCMC, or the National Union Catalog of Manuscript Collections, is a free-of-charge cooperative cataloging program operated by the Library of Congress. ... Close to 500,000 records available in the Research Libraries Information Network bibliographic database, for archival and manuscript collections in research libraries, museums, state archives, and historical societies located throughout North America ... can be searched via a catalogue gateway provided by the Library of Congress. The access to the gateway is free of charge.