Federal Library Depository Directory
Searchable directory of Depository Libraries - those with extensive, official collections of federal government documents.
Library of Congress Catalogs
Browse or search using several options. Also provides links to additional library catalogs.
Library Spot: Libraries Online
Link to lists of libraries of all types, and their catalogs.
NLM Locator Plus
Search the catalog of the National Library of Medicine. Also links to Medline.
Smithsonian Institution Research Information System
Search the catalogs, archives, inventories, research collections, etc. of 20 museum and gallery libraries.
Catalog of materials in libraries worldwide.