The United States of America : www.firstgov.gov
The White House (The President of the United States) : www.whitehouse.gov
The United States House of Representatives : www.house.gov
Speaker of the House : speaker.house.gov
The United States Senate : www.senate.gov
President Pro Tem of the Senate : stevens.senate.gov/protem.cfm
Library of Congress : www.loc.gov
The Supreme Court of the United States : www.supremecourtus.gov
Department of Agriculture : www.usda.gov
US Forest Service : www.fs.fed.us
Department of Commerce : www.commerce.gov
National Aviation and Space Administration (NASA) : www.nasa.gov
National Oceanic and Atmospheric Administration : www.nws.noaa.gov
US Census Bureau : www.census.gov
U.S. Patent and Trademark Office : www.uspto.gov
Department of Defence : www.defenselink.mil
US Air Force : www.af.mil
US Army : www.army.mil
US Coast Gaurd : www.uscg.mil
US Marine Corps : www.marines.mil
US Navy : www.navy.mil
Department of Education : www.ed.gov
Environmental Protection Agency : www.epa.gov
Department of Energy : www.energy.gov
Department of Health and Human Services : www.dhhs.gov
Food and Drug Administration : www.fda.gov
National Institute of Health : www.nih.gov
Department of Housing and Urban Development : www.hud.gov
Department of Homeland Security : www.dhs.gov
Department of the Interior : www.doi.gov
National Park Service : www.nps.gov
Department of Justice : www.usdoj.gov
Federal Bureau of Investigation (FBI) : www.fbi.gov
Department of Labor : www.dol.gov
Department of State : www.state.gov
Department of the Treasury : www.ustreas.gov
Bureau of Engraving & Printing : www.moneyfactory.com
US Mint : www.usmint.gov
Department of Transportation : www.dot.gov
Department of Veterans Affairs : www.va.gov
National Archives : www.archives.gov
Smithsonian Institute : www.si.edu