Federal

Executive

Office of Management and Budget
The White House

Congress

Library of Congress
U.S. House Of Representatives
U.S. Senate

Departments

U.S. Department of Agriculture - AGRIC
U.S. Department of Commerce - COMM
U.S. Department of Defense - DOD
U.S. Department of Education - ED
U.S. Department of Homeland Security - DHS 
U.S. Department of Housing and Urban Development - HUD
U.S. Department of Interior - INTER
U.S. Department of Justice - JUSTC
U.S. Department of Labor - LABOR
U.S. Department of State - STATE
U.S. Department of Transportation - TRANS

Agencies

Center for Disease Control - CDC
Congressionally Directed Medical Research Programs - CDMRP
Cooperative State Research, Education, and Extension Service - AGRIC CSREES
Environmental Protection Agency - EPA
National Aeronautics and Space Administration - NASA
National Endowment for the Arts - NEA
National Endowment for the Humanities - NEH
National Institutes of Health - NIH
National Science Foundation - NSF