NUCMC is the abbreviation for the National Union Catalog of Manuscript Collections.
It is a national-level program based at the Library of Congress that seeks to promote free access to the documentary heritage of the United States.
It does this by providing cataloging for archives and historical societies around the country that do not have access to national online databases.
[2] One famed editor was Arline Custer, Head of the Manuscript Section, Descriptive Cataloging Division of the Library of Congress.
[2] As of 1986, the cataloging records were input into RLIN, the Research Libraries Information Network, an international online database.