Many of the departments and agencies of the U.S. government are involved in research and development, and fund their own libraries to support those efforts. The catalogs of those libraries are increasingly available on the web to anyone, and can serve as excellent research tools for academic purposes. In many cases, the libraries are very specialized. Often the books and journal articles listed are available through interlibrary loan. There also may be specialized research tools on the library web site, such as bibliographies.

The libraries linked on this page represent some of the large and well-known libraries in the federal government. To locate others, search the individual agency web site. You might also want to consult the FirstGov.gov Federal Libraries page, which links to many additional Federal libraries.

The U.S. Congress has authorized four Federal libraries to be called "national libraries."

• Library of Congress
• National Agricultural Library
• National Library of Education
• National Library of Medicine

• Dept. of Commerce Departmental Library
• Dept. of Defense Defense Technical Information Center
• Dept. of Defense Pentagon Library
• Dept. of Defense U.S. Army Europe Libraries
• Dept. of Interior Library
• Dept. of Labor Wirtz Labor Library
• Environmental Protection Agency National Library Network
  
• National Institute of Environmental Health Sciences Library
• National Institute of Standards and Technology Virtual Library
• National Institutes of Health Library
• National Oceanic & Atmospheric Administration Central Library
• National Transportation Library
• Presidential Libraries
• Smithsonian Institution Research Information System (SIRIS)
• U.S. Geological Survey Library
• U.S. Institute of Peace Jeannette Rankin Library