To research American Folklife Center collections, a good place to start is the Library of Congress Online Catalog. Each AFC collection has an individual catalog record. The following link provides a custom search in the catalog for Puerto Rico materials:
Finding aids provide a gateway to a wealth of Library of Congress treasures. These guides provide comprehensive overviews of unique Library resources. Progressively detailed descriptions of a collection's component parts summarize the overall scope of the content, convey details about the individuals and organizations involved, and list box and folder headings. The link below is a customized search of Library of Congress Finding Aids limited to finding aids in the American Folklife Center collections relating to Puerto Rico.
Over a period of forty years, AFC staff compiled meticulous guides to archival collection material by state or geographic locality. While these are no longer maintained, they provide information at a more granular level than found in the Library's Online Catalog. Below is the guide to Puerto Rico.
This guide provides research strategies for using American Folklife Center collections.