Notes:

1. Unless indicated otherwise, individual people working at agencies do not tweet on behalf of their agencies.
2. Any people listed, other than members of Congress, do not necessarily represent their agencies
3. If you notice anyone or anything missing, feel free to contact Ari Herzog via Twitter or E-mail.

Executive Branch (including Cabinet, departments, and agencies)

• The White House: Communications Office
• The White House: Office of National Drug Control Policy
• Department of Agriculture: Food Safety Information Center
• Department of Commerce: National Oceanic and Atmospheric Administration: National Marine Sanctuary
• Department of Defense: Maxine Teller, Public Affairs
• Department of Defense: Mark Drapeau, Research Fellow, National Defense University
• Department of Defense: US Joint Forces Command
• Department of Defense: Department of Army: US Army
• Department of Defense: Department of Navy: Naval Air Warfare Center Weapons Division: HJ Armstrong, public affairs
• Department of Energy: Argonne National Laboratory
• Department of Health & Human Services: AIDS.gov
• Department of Health & Human Services: National Institutes of Health: NIH Communications Office
• Department of Health & Human Services: National Institutes of Health: Jim Angus
• Department of Health & Human Services: Office on Women's Health
• Department of Homeland Security: Leadership Journal
• Department of Homeland Security: Transportation Security Administration blog team
• Department of Homeland Security: US Citizenship and Immigration Services
• Department of Interior: National Park Service: Brooks Camp at Katmai National Park
• Department of Interior: National Park Service: National Center for Preservation Technology & Training
• Department of State: Country-specific Information, travel department
• Department of State: Dipnote, official blog feed
• Department of State: US Embassy, London
• Environmental Protection Agency: EPA
• Environmental Protection Agency: Greenversations blog
• Federal Energy Regulatory Commission: FERC
• General Services Administration: Federal Citizen Information Center
• General Services Administration: Office of Citizen Services and Communications: GovGab
• General Services Administration: Office of Citizen Services and Communications: GobiernoUSA.gov
• General Services Administration: Office of Citizen Services and Communications: USA.gov
• National Aeronautics and Space Administration: Astrobiology Institute
• National Aeronautics and Space Administration: CoLab, advising and consulting on NASA collaboration
• National Aeronautics and Space Administration: Desert RATS
• National Aeronautics and Space Administration: Earth Observatory, echoed at Natural Hazard
• National Aeronautics and Space Administration: GLAST
• National Aeronautics and Space Administration: Hubble Space Telescope
• National Aeronautics and Space Administration: Jason-1 project
• National Aeronautics and Space Administration: Kepler
• National Aeronautics and Space Administration: Lunar Atmosphere & Dust Environment Explorer
• National Aeronautics and Space Administration: Lunar Crater Observation & Sensing Satellite
• National Aeronautics and Space Administration: Lunar Reconnaissance Orbiter
• National Aeronautics and Space Administration: NanoSail-D mission, first solar sail created for nanosatellites
• National Aeronautics and Space Administration: NASA EDGE
• National Aeronautics and Space Administration: PharmaSat
• National Aeronautics and Space Administration: PreSat
• National Aeronautics and Space Administration: Public Affairs
• National Aeronautics and Space Administration: Solar Dynamics Observatory
• National Aeronautics and Space Administration: Transiting Exoplanet Survey Satellite
• National Aeronautics and Space Administration: Emma Antunes, web manager
• National Aeronautics and Space Administration: Ames Research Center: Public Affairs Office
• National Aeronautics and Space Administration: Ames Research Center: Kimberly Ennico, payload scientist
• National Aeronautics and Space Administration: Goddard Space Flight Center: Linda Cureton, chief information officer
• National Aeronautics and Space Administration: Goddard Space Flight Center: Ravi Sharma, engineer
• National Aeronautics and Space Administration: Innovative Partnerships Program: Doug Comstock, director
• National Aeronautics and Space Administration: Jet Propulsion Laboratory: Cassini, flying around Saturn
• National Aeronautics and Space Administration: Jet Propulsion Laboratory: Earth Vital Signs
• National Aeronautics and Space Administration: Jet Propulsion Laboratory: Mars Exploration Rover
• National Aeronautics and Space Administration: Jet Propulsion Laboratory: News, unofficial feed, not endorsed by JPL
• National Aeronautics and Space Administration: Jet Propulsion Laboratory: Phoenix Mars Lander
• National Aeronautics and Space Administration: Langley Research Center: Bil Kleb, computational aerothermodynamist
• National Aeronautics and Space Administration: Marshall Space Flight Center: Daniel Kanigan, public affairs
• National Geospatial-Intelligence Agency: Chris Rasmussen, social software knowledge manager/trainer
• Office of Personnel Management: OPM
• Securities and Exchange Commission: SEC Investor Education
• Social Security Administration: Lee Alviar, public affairs specialist in Dallas
• U.S. Geological Survey: USGS
• U.S. Geological Survey: Earthquake & Tsunami Warning
• U.S. Geological Survey: Dave Govoni, paleontologist
• U.S. Intelligence Community: Andrea Baker
• U.S. Intelligence Community: Heather Cox
• U.S. Intelligence Community: John Hale
• U.S. Peace Corps
• U.S. Small Business Administration: Business.Gov

Legislative Branch: U.S. Senate

• Votes from the Senate floor

1. Joe Biden (D), U.S. Senator from Delaware, presidential candidate in 2008
2. Hillary Clinton (D), U.S. Senator from New York, former First Lady of the United States, presidential candidate in 2008
3. James DeMint (R), U.S. Senator from South Carolina
4. Chris Dodd (D), U.S. Senator from Connecticut, presidential candidate in 2008
5. Chuck Grassley (R), U.S. Senator from Iowa
6. Kay Hagan (D), U.S. Senator-elect from North Carolina
7. James Inhofe (R), U.S. Senator from Oklahoma
8. Barack Obama (D), U.S. Senator from Illinois, presidential candidate in 2008

Legislative Branch: House of Representatives

• Votes from the House floor
• House Republican Conference Committee
• House Republican Policy Committee

1. Neil Abercrombie (D), U.S. Representative from Hawaii
2. Gresham Barrett (R), U.S. Representative from South Carolina
3. Roy Blunt (R), U.S. Representative from Missouri, Minority Whip
4. John Boehner (R), U.S. Representative from Ohio, Minority Leader; also runs GOP Leader
5. John Boozman (R), U.S. Representative from Arkansas
6. Michael Burgess (R), U.S. Representative from Texas
7. Dan Burton (R), U.S. Representative from Indiana
8. Eric Cantor (R), U.S. Representative from Virginia
9. John Culberson (R), U.S. Representative from Texas
10. Keith Ellison (D), U.S. Representative from Minnesota
11. Randy Forbes (R), U.S. Representative from Virginia
12. Pete Hoekstra (R), U.S. Representative from Michigan
13. Randy Kuhl (R), U.S. Representative from New York
14. Tom Latham (R), U.S. Representative from Iowa
15. Robert Latta (R), U.S. Representative from Ohio
16. Ileana Ros-Lehtinen (R), U.S. Representative from Florida
17. Thaddeus McCotter (R), U.S. Representative from Michigan
18. Kendrick Meek (D), U.S. Representative from Florida
19. Candice Miller (R), U.S. Representative from Michigan
20. George Miller (D), U.S. Representative from California; also runs Educ & Labor Democrats
21. Nancy Pelosi (D), U.S. Representative from California, Speaker of the House
22. Tom Price (R), U.S. Representative from Georgia
23. Dennis Rehberg (R), U.S. Representative from Montana
24. Tim Ryan (D), U.S. Representative from Ohio
25. Christopher Shays (R), U.S. Representative from Connecticut
26. John Shimkus (R), U.S. Representative from Illinois
27. Mark Udall (D), U.S. Representative from Colorado
28. Tom Udall (D), U.S. Representative from New Mexico
29. Joe Wilson (R), U.S. Representative from South Carolina
30. Rob Wittman (R), U.S. Representative from Virginia
31. John Yarmuth (D), U.S. Representative from Kentucky
32. Ron Paul (L), U.S. Representative from Texas

Former U.S. Legislators

• Bob Barr (L), former U.S. Representative from Georgia, presidential candidate in 2008
• John Edwards (D), former U.S. Senator from North Carolina, presidential candidate in 2004 and 2008

Resources

1. Congresspedia provides more information on members of Congress.
2. AlleyInsider posted about government agencies on Twitter.