| Y 3.Im 6 | Immigration Commission (1907-1910) |
| Y 3.Im 6/2 | Select Commission on Immigration and Refugee Policy (1978- 1980) |
| Y 3.In 2/1 | Indian Currency Commission (Great Britain) (1893) |
| Y 3.In 2/2 | Industrial Commission (1899-1902) |
| Y 3.In 2/3 | Joint Commission to Investigate Indian Affairs (1914-1915) |
| Y 3.In 2/4 | Commission on Industrial Relations (1913-1916) |
| Y 3.In 2/5 | Committee on Industrial Analysis (1936-1937) |
| Y 3.In 2/6 | Indian Claims Commission (1946-1978) |
| Y 3.In 2/7 | Commission on Increased Industrial Use of Agricultural Products (1956-1973) |
| Y 3.In 2/8 | National Industrial Pollution Control Council (1970-1973) |
| Y 3.In 2/9 | National Council on Indian Opportunity (1968-1974) |
| Y 3.In 2/10 | National Advisory Council on Indian Education (1965- ) |
| Y 3.In 2/11 | National Commission for Industrial Peace (1973-1974) |
| Y 3.In 8 | International Exchange Commission (1903-1904) |
| Y 3.In 8/2 | Interdepartmental Social Hygiene Board (1918-1923) |
| Y 3.In 8/3 | Interdepartmental Committee to Coordinate Health and Welfare Activities (1935-1939) |
| Y 3.In 8/4 | Interdepartmental Committee on Scientific Research and Development (1947-1959) |
| Y 3.In 8/5 | International Development Advisory Board (1950-1955) |
| Y 3.In 8/6 | Interdepartmental Committee on Children and Youth (1948-1973) |
| Y 3.In 8/7 | Intergovernmental Relations Commission (1953-1955) |
| Y 3.In 8/8 | Interagency Committee on Water Resources (1954- 1956) |
| Y 3.In 8/9 | Interdepartmental Committee on narcotics (1951-1970) |
| Y 3.In 8/10 | Interdepartmental Committee for the Study of Jurisdiction over Federal Areas within the States (1954-1957) |
| Y 3.In 8/11 | Interagency Committee on Agricultural Surplus Disposal (1954-1956) |
| Y 3.In 8/12 | Interdepartmental Committee on Radiation Preservation of Food (1956) |
| Y 3.In 8/13 | Interdepartmental Committee on Nutrition for National Defense (1954) |
| Y 3.In 8/14 | Interdepartmental Committee on Civilian Compensation (1958) |
| Y 3.In 8/15 | Commission on International Rules of Judicial Procedure (1958) |
| Y 3.In 8/16 | Interagency Committee on Automatic Data Processing (1960) |
| Y 3.In 8/17 | Interdepartmental Committee to Coordinate Federal Urban Area Assistance Programs (1959) |
| Y 3.In 8/18 | Interdepartmental Highway Safety Board (1960-1970) |
| Y 3.In 8/19 | Interdepartmental Federal Tort Claims Committee (1960) |
| Y 3.In 8/20 | Interagency Committee on International Athletics (1963) |
| Y 3.In 8/21 | Interdepartmental Committee on the Status of Women (1963- 1978) |
| Y 3.In 8/22 | Interagency Committee on Export Expansion (1963-1973) |
| Y 3.In 8/23 | Interagency Committee on Mexican American Affairs (1967-1969) |
| Y 3.In 8/24 | Interstate commission on the Potomac River Basin (1976- ) |
| Y 3.In 8/25 | Inter-American Foundation (1969- ) |
| Y 3.In 8/26 | Interagency Committee on Intermodal Cargo (1978-?) |
| Y 3.In 8/27 | Office of the Federal Inspector for the Alaska Natural Gas Transportation System (1979-1992) |
| Y 3.In 8/28 | International Joint Commission United States and Canada (1911- ) |
| Y 3.In 8/29 | Interagency Task Force on Small Business Finance (?-1982) |
| Y 3.In 8/29-2 | Interparliamentary Union, United States Group (verify stem; 8/30?) |
| Y 3.In 8/31 | Interagency Task Force on Acid Precipitation (1980-?) |
| Y 3.Ir 6 | Board for Testing Iron, Steel, and Other Metals (1875-1881) |
| Y 3.Is 7 | Isthmian Canal Commission (1899-1902) |
