| Mark | Year | Entries | |
| Illinois. Criminal Court (Cook County) | 1924 | 1 | |
| Illinois Criminal Justice Information Authority | 2000 | 1 | |
| Illinois. Day Care, Governor's Task Force on -- See Illinois. Governor's Task Force on Day Care | 1 | ||
| Illinois. Department de Servicios Humanos de Illinois -- See Illinois. Department of Human Services | 1 | ||
| Your entry Illinois. Department for Exceptional Children would be here | |||
| Illinois. Department of Administrative Services -- See Also the earlier heading Illinois. Department of Finance | 1 | ||
| Illinois. Department of Adult, Vocational, and Technical Education | 1978? | 1 | |
| Illinois. Department of Aeronautics | 1946 | 1 | |
| Illinois. Department of Agriculture | 4 | ||
| Illinois. Department of Alcoholism & Substance Abuse -- See Also the later heading Illinois. Department of Human Services | 1 | ||
| Illinois. Department of Business and Economic Development -- 2 Related Authors | 2 | ||
| Illinois. Department of Business and Economic Development | 3 | ||
| Illinois. Department of Business and Economic Development. Division of Energy -- See Illinois. Division of Energy | 1 | ||
| Illinois. Department of Business Services. | 1995 | 1 | |
| Illinois. Department of Children and Family Services. | 4 | ||
| Illinois. Department of Commerce and Community Affairs -- 3 Related Authors | 3 | ||
| Illinois. Department of Commerce and Community Affairs. | 1988- | 1 | |
| Illinois. Department of Commerce and Economic Opportunity -- See Also the earlier heading Illinois. Department of Commerce and Community Affairs | 1 | ||
| Illinois. Department of Commerce and Economic Opportunity. | 2004 | 1 | |
| Illinois. Department of Conservation -- 2 Related Authors | 2 | ||
| Illinois. Department of Conservation. | 8 | ||
| Illinois. Department of Conservation. Division of Historic Sites -- See Illinois. Division of Historic Sites | 1 | ||
| Illinois. Department of Conservation, Parks, and Memorials -- See Illinois. Department of Conservation | 1 | ||
| Illinois. Department of Corrections. State Penitentiary (Joliet, Ill.) -- See Illinois State Penitentiary (Joliet, Ill.) | 1 | ||
| Illinois. Department of Employment Security | 2004 | 1 | |
| Illinois. Department of Energy and Natural Resources -- See Also the earlier heading Illinois Institute of Natural Resources | 1 | ||
| Illinois. Department of Energy and Natural Resources. | 3 | ||
| Illinois. Department of Energy and Natural Resources. Office of Scientific Research and Analysis. Natural History Survey Division -- See Illinois. Natural History Survey Division | 1 | ||
| Illinois. Department of Energy and Natural Resources. State Geological Survey -- See Illinois State Geological Survey | 1 | ||
| Illinois. Department of Energy and Natural Resources. State Water Survey -- See Illinois State Water Survey | 1 | ||
| Illinois. Department of Healthcare and Family Services -- See Also the earlier heading Illinois. Department of Public Aid | 1 | ||
| Illinois. Department of Human Services -- See Also Illinois. Division of Disability and Behavioral Health Services | 1 | ||
| Illinois. Department of Human Services. | 2 | ||
| Illinois. Department of Human Services. Division of Disability and Behavioral Health Services -- See Illinois. Division of Disability and Behavioral Health Services | 1 | ||
| Illinois. Department of Insurance, | 2008- | 1 | |
| Illinois. Department of Labor -- 2 Related Authors | 2 | ||
| Illinois. Department of Labor. Division of Placement and Unemployment Compensation -- See Illinois. Division of Unemployment Compensation | 1 | ||
| Illinois. Department of Labor. Division of Unemployment Compensation -- See Illinois. Division of Unemployment Compensation | 1 | ||
| Illinois. Department of Labor. Governor's Committee on Unemployment -- See Illinois. Governor's Committee on Unemployment | 1 | ||
| Illinois. Department of Law Enforcement -- See Also Illinois. Bureau of Identification | 1 | ||
| Illinois. Department of Law Enforcement. Bureau of Identification -- See Illinois. Bureau of Identification | 1 | ||
| Illinois. Department of Law Enforcement. Division of State Police -- See Illinois State Police | 1 | ||
| Illinois. Department of Law Enforcement. State Police -- See Illinois State Police | 1 | ||
| Illinois. Department of Local Government Affairs -- See Also the later heading Illinois. Department of Commerce and Community Affairs | 1 | ||
| Illinois. Department of Local Government Affairs | 1976 | 1 | |
| Illinois. Department of Mental Health -- 2 Related Authors | 2 | ||
| Illinois. Department of Mental Health. | 3 | ||
| Illinois. Department of Mental Health and Developmental Disabilities -- 2 Related Authors | 2 | ||
| Illinois. Department of Mental Health. Institute for Juvenile Research -- See Institute for Juvenile Research (Ill.) | 1 | ||
| Illinois. Department of Military Affairs | 1 | ||
| Illinois. Department of Mines and Minerals -- 2 Related Authors | 2 | ||
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