Archive Finder ArchivesUSA Archive Finder, a directory of over 5,400 repositories and over 220,000 collections of primary source materials across the United States, United Kingdom and Ireland. Included are the National Union Catalog of Manuscript Collections (1959 to current), the contents from National Inventory of Documentary Sources in the United States, and collection descriptions submitted directly from repositories as well as links to online finding aids. Dates of Coverage: varies by title.