Federal Funding Agencies
26 Federal Agencies that Provide Grants
http://www.grants.gov/applicants/agencies_that_provide_grants.jsp
note: in the US Department of Defense, look for the Air Force, Army, Navy, Marine Corps, Coast Guard, the Department of Health and Human Services(DHHS) includes the National Institutes of Health (NIH )and the National Institute of Mental Health (NIMH)
National-level agencies that sometimes provide grant opportunities, though doing so is not their primary purpose:
The White House Fellowships
http://www.whitehouse.gov/fellows/
The Smithsonian Office of Research Training and Services
http://www.si.edu/ofg/start.htm
USIA United States Information Agency
Center for Disease Control
https://www.cia.gov/
Central Intelligence Agency
https://www.cia.gov/
Defense Advanced Research Projects Agency (DARPA)
http://www.arpa.mil/
Defense Logistics Agency
http://www.dla.mil/
National Institutes of Health (NIH)
http://www.nih.gov/
National Oceanic and Atmospheric Administration
http://www.noaa.gov/
Office of Juvenile Justice and DelinquencyPrecvention (OJJDP)
http://ojjdp.ncjrs.org/
The National Labs (also listed in the Department of Energy)
Sandia National Lab
http://www.sandia.gov/
Argonne National Laboratory
http://www.argonne.gov/
Brookhaven National Lab
http://www.bnl.gov/
Lawrence Livermore National Laboratory
http://www.llnl.gov/
Oak Ridge National Laboratory (ORNL)
http://www.ornl.gov/
Lawrence Berkeley National Laboratory
http://www.lbl.gov/
Los Alamos National Laboratory
http://www.lanl.gov/
The Pacific Northwest National Laboratory.
http://www.pnl.gov/