| Y 3.Sa 2 | Saint Lawrence Seaway Development Corporation (1954- 1966) |
| Y 3.Sa 2/2 | Saint Augustine Quadricentennial Commission (1962) |
| Y 3.Sa 5 | Santo Domingo Commission (1871) |
| Y 3.Se 4 | Selective Service System (1948- ) |
| Y 3.Se 5 | United States Sentencing Commission (1987- ) |
| Y 3.Se 5/2 | Commission on the Bicentennial of the U.S. Senate |
| Y 3.Se 5/3 | National Advisory Committee on Semiconductors (1988-1992) |
| Y 3.Sh 6 | Ship Structure Committee (1946- ) |
| Y 3.Sh 6/2 | American Shipbuilding Commission (1970-1973) |
| Y 3.Si 2 | Joint Commission to Consider the Present Organization of the Signal Service, Geological Survey, Coast and Geodetic Survey, and Hydrographic Office (1886) |
| Y 3.So 1 | National Commission on Social Security (1977-1981) |
| Y 3.So 8 | Souris-Red-Rainy River Basins Commission (1967-1973) |
| Y 3.So 8/2 | Southwest Border Regional Commission (1965-1981) |
| Y 3.Sp 1 | National Commission on Space (1984-1986) |
| Y 3.Sp 2/2 | Spanish Treaty Claims Commission (1901-1910) |
| Y 3.Sp 2/7 | Cabinet Committee on Opportunity for the Spanish Speaking Peoples (1970- 1974) |
| Y 3.St 8 | Strategy Council on Drug Abuse (1972-1980) |
| Y 3.St 9 | National Commission on Student Financial Assistance (1980-?) |
| Y 3.Su 1 | Subversive Activities Control Board (1950-1973) |
| Y 3.Su 3 | Sugar Equalization Board (1918-1926) |
| Y 3.Su 7 | Federal Board of Surveys and Maps (1936-1942) |
| Y 3.Su 7/2 | National Commission on Supplies and Shortages (1974- 1977) |
| Y 3.Su 7/3 | National Commission on Superconductivity |
