| Code | Department |
| A |
Agriculture Department |
| C |
Commerce Department |
| C 3. |
Census Bureau (Commerce Department) |
| D |
Defense Department |
| E |
Energy Department |
| ED |
Education Department |
| GA |
General Accounting Office |
| GS |
General Services Administration |
| HE |
Health and Human Services Department |
| I |
Interior Department |
| I 19. |
U.S. Geological Survey (Interior Department) |
| J |
Justice Department |
| Ju |
Judiciary |
| L |
Labor Department |
| LC |
Library of Congress |
| NAS |
National Aeronautics and Space Administration |
| S |
State Department |
| SI |
Smithsonian Institution |
| T |
Treasury Department |
| T 22. |
Internal Revenue Service (Treasury Department) |
| X, Y |
Congress |
| Y4 |
Congressional Committees |