National Agricultural Library 
Part of the Agricultural Research Service of the US Department of Agriculture.
http://www.nalusda.gov/National Library of Medicine
US national provider of health-related library and information services.
http://www.nlm.nih.gov/
National Institutes of Health Library
Serving the US National Institutes of Health, with self-service access to others.
http://nihlibrary.nih.gov/
Herbert C. Hoover Building Library
Serving the US Department of Commerce.
http://www.osec.doc.gov/lib/
US National Information Infrastructure Virtual Library
Access to documents and information for the US component of Global Inventory Project (GIP) and the international registry for the G8 Global for Small and Medium-Sized Enterprises (SME) Testbeds.
http://nii.nist.gov/
U.S. Department of the Interior Library
Focusing on the natural and social sciences; law; economics; management and use of natural and cultural resources; and the cultures and well-being of American Indians and Native Alaskans.
http://library.doi.gov/
The National Transportation Library
US repository for transportation information.
http://ntl.bts.gov/
Canada Instititue for Scientific and Technical Information
Canadian research library for science, technology, engineering, and medicine.
http://cisti-icist.nrc-cnrc.gc.ca/
National Library of Education
US federal government's resource center for education information.
http://ies.ed.gov/ncee/projects/nat_ed_library.asp
