Author & Contributor Index
- Illinois. Division of Wildlife Resources
- Illinois Environmental Protection Agency
- Illinois Environmental Protection Agency. Bureau of Water
- Illinois Environmental Protection Agency. Lake and Watershed Unit
- Illinois Farm Bureau
- Illinois Farm Bureau. Farm Management Service
- Illinois Fire Service Institute
- Illinois Fire Service Institute
- Illinois Fire Service Institute,
- Illinois. Framework Advisory Committee
- Illinois. General Assembly. Senate. Geologic Map Task Force
- Illinois. General Assembly. Senate. Working Committee on Geologic Mapping
- Illinois Geological Society
- Illinois Global Climate Change Program, Illinois State Water Survey
- Illinois Groundwater Consortium
- Illinois. Hazardous Waste Research and Information Center
- Illinois Heritage Association
- Illinois Historical Survey
- Illinois-Indiana Sea Grant
- Illinois-Indiana Sea Grant College Program
- Illinois-Indiana Sea Grant, Illinois Natural History Survey
- Illinois-Indiana Sea Grant Program
- Illinois. Institute for Environmental Quality
- Illinois. Institute for Social Policy
- Illinois Institute of Natural Resources
- Illinois Institute of Natural Resources, State Water Survey Division
- Illinois Institute of Technology
- Illinois International High School Initiative
- Illinois. Interstate Oil Compact Commission
- Illinois. Lake Michigan Coast and Basin Studies
- Illinois. Land Reclamation Division
- Illinois Master Plumbers' Association
- Illinois Mineral Industries Committee
- Illinois Mine Subsidence Insurance Fund
- Illinois Mine Subsidence Research Program
- Illinois Museum of Natural History
- Illinois. National History Survey Division
- Illinois Natural History Society,
- Illinois Natural History Survey
- Illinois Natural History Survey,
- Illinois. Natural History Survey. Center for Biodiversity
- Illinois Natural History Survey Division
- Illinois. Natural History Survey Division. Aquatic Biology Section
- Illinois. Natural History Survey Division. Center for Aquatic Biology
- Illinois. Natural History Survey Division. Center for Biodiversity
- Illinois. Natural History Survey Division. Center for Biogeographic Information
- Illinois. Natural History Survey Division. Center for Wildlife Ecology
- Illinois. Natural History Survey Division. Division of Fisheries
- Illinois. Natural History Survey Division. Economic Entomology Section
- Illinois. Natural History Survey Division. Lake Michigan Biological Station