A very useful guide to locating archives around the world. Information can be searched by topic or specific archive. New resources are continually added.
Online Archive of California (OAC)
Provides access to descriptions and finding aids for materials such as manuscripts, photographs, and works of art held in libraries, museums, archives, and other institutions across California.
Library of Congress Finding Aids
Archival finding aids are detailed guides to primary source material which provide fuller information than that normally contained within cataloging records. This page provides links to online archival finding aids at the Library of Congress.
National Register of Archives
The NRA contains information on the nature and location of manuscripts and historical records that relate to British history.
Repositories of Primary Sources
"A listing of over 5,000 websites describing library holdings of manuscripts, archives, rare books, historical photographs, and other primary sources for the research scholar." (University of Idaho)
Getty Research: Search the Research Library Catalog, find Special Collections Finding Aids, browse digital images and resources, or access various databases such as the Provenance Index, the Art & Architecture Thesaurus®, and the Union List of Artist Names®.
Museum of Modern Art (MoMA) Online Collection: 7,717 Artists and 44,891 Works Online