U.S. Government

The Legislative Branch of the U.S. Government 

The U.S. Congress

The House of Representatives
The U.S. Senate
Biographical Directory of the United States Congress (1774-Present)
U.S. Library of Congress - Thomas -- Legislative information on the Internet

The Executive Branch of the U.S. Government

The White House

White House
Executive Office of the President
National Security Council

Departments of the Government

Department of Agriculture
Department of Commerce
Department of Defense
Department of Education
Department of Energy
Department of Health & Human Services
Department of Homeland Security
Department of Housing & Urban Development
Department of the Interior
Department of Justice
Department of Labor
Department of State
Department of Transportation
Department of Treasury
Department of Veterans Affairs

Federal Agencies and Institutions

Central Intelligence Agency (CIA)
Environmental Protection Agency (EPA)
Federal Aviation Administration (FAA)
Federal Bureau of Investigation (FBI)
Food and Drug Administration (FDA)
Government Printing Office (GPO)
Library of Congress (LOC)
National Aeronautics and Space Administration (NASA)
National Endowment for the Arts
National Institutes of Health (NIH)
National Park Service
Peace Corps
Smithsonian Institution
U.S. Agency for International Development (USAID)
U.S. Census Bureau (Statistical Information)
U.S. International Trade Commission

The Judicial Branch of the U.S. Government

U.S. Supreme Court
U.S. Courts

U.S. Diplomatic Missions

U.S. Embassies
U.S. Mission to the United Nations in New York
U.S. Mission to the United Nations in Geneva
U.S. Mission to UNESCO
U.S. Fund for UNICEF  
U.S. Mission to the European Union
U.S. Mission to NATO
U.S. Mission to the OSCE