This is the only reference that I could find for the Central Location Index: JDC - Archives : Central Location Index 1946-1949. It does not give any explanation of what the organization did. The International Tracing Service was the primary organization for tracing people that disappeared during the Holocaust Arolsen Archives - International Center on Nazi Persecution - Wikipedia
Thank you Susannah - That is about all the information I was able to locate also. Will keep searching.
Dear Mr. Blum,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located the series General Records of Registered Agencies, 1942-1948 in the Records of Temporary Committees, Commissions, and Boards (Record Group 220) that contains some information about the Central Location Index. These records were created by President Roosevelt's War Relief Control Board and by the subsequent Advisory Committee on Voluntary Foreign Aid. The records have not been digitized. For access to and information about them, please contact the National Archives at College Park - Textual Reference (RDT2) at firstname.lastname@example.org.
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In addition, we searched WorldCat and located 7 records related to "Central Location Index", and we searched the SNAC (Social Networks and Archival Context) Cooperative and located 1 resource related to the Central Location Index that may be of interest to you.
More information about the Central Location Index may be located online at EHRI - Central Location Index of the Relatives Search Department, and Central Location Index History.
We hope this information is helpful. Best of luck with your research!
Thank you Ms. Salyer - the file from the JDC which was under the Central Location Index History link contained exactly the information I was seeking.