Charadrius melodus Ord 1824
Illinois and Federally Endangered 
photo credit: US Fish and Wildlife Service
                            
                                                                Cyprogenia stegaria Rafinesque, 1820
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
Dalea foliosa (A. Gray) Barneby
Illinois and Federally Endangered
photo credit: Global Biodiversity Information Facility and iNaturalist 
Myotis grisescens A. H. Howell, 1909
Illinois and Federally Endangered
photo credit: Michael Durham via Illinois Department of Natural Resources
                            
                                                                Bombus affinis Cresson 1863
Illinois and Federally Endangered
photo credit: US Fish and Wildlife Service
                            
                                                                Scaphirhynchus albus (Forbes and Richardson, 1905)
Illinois and Federally Endangered
photo credit: Ryan Hagerty, US Fish and Wildlife Service
                            
                                                                Sistrurus catenatus (Rafinesque-Schmaltz, 1818)
Illinois Endangered and Federally Threatened
photo credit: Illinois Natural History Survey
                            
                                                                Lycaeides melissa samuelis Nabokov, 1944
Illinois and Federally Endangered
photo credit: Jill Utrup, U.S. Fish and Wildlife Service via NatureServe
                            
                                                                Tetraneuris herbacea Greene
Illinois Endangered and Federally Threatened
image credit: Britton, N.L., and A. Brown, 1913, An illustrated flora of the northern United States, Canada and the British Possessions.
                            
                                                                Emydoidea blandingii (Holbrook, 1838)
Illinois Endangered and under review for federal listing
photo credit: Illinois Natural History Survey
                            
                                                                Potamilus capax (Green, 1832)
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Asclepias meadii Torr. ex A. Gray
Illinois Endangered and Federally Threatened
photo credit: US Forest Service 
                            
                                                                Pleurobema clava (Lamarck, 1819)
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Plethobasus cooperianus (Lea, 1834)
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Ixobrychus exilis (Gmelin, 1789)
Illinois Threatened, not listed federally
photo credit: Steve Arena/USFWS
                            
                                                                Lampsilis higginsii (Lea, 1857)|
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Clonophis kirtlandii (Kennicott, 1856)
Illinois Threatened and not listed federally
                            
                                                                Plethobasus cyphyus (Rafinesque, 1820)
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Lampsilis abrupta (Say, 1831)
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Somatochlora hineana Williamson, 1931
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Cumberlandia monodonta (Say, 1829)
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Epioblasma triquetra (Rafinesque, 1820)
Illinois and Federally Endangered
photo credit: Illinois Natural History Survey
                            
                                                                Epioblasma rangiana (Lea, 1839)
Illinois and Federally Endangered, extirpated from Illinois
photo credit: Illinois Natural History Survey
                            
                                                                Calidris canutus rufa
Illinois and Federally Threatened
photo credit: Gregory Breese/USFWS 
                            
                                                                Leptodea leptodon (Rafinesque, 1820)
Illinois and Federally Endangered, likely extirpated from Illinois
photo credit: Illinois Natural History Survey
Canis lupus Liinnaeus, 1u58
Illinois and Federally Endangered 
photo credit: Mary Kay Rubey via Illinois Department of Natural Resources
Poliocitellus franklinii (Sabine, 1822)
Illinois Threatened and not listed federally
photo credit: Illinois Department of Natural Resources
                            
                                                                Cryptobranchus alleganiensis (Daudin, 1803)
Illinois Endangered, not listed federally
photo credit: C.A. Phillips, Illinois Natural History Survey
 
Federally listed species are by definition listed in Illinois, although not all federally listed species occur in Illinois. Additional species not listed at the federal level are listed by the state for protection based on the Illinois Endangered Species Protection Act and criteria outlined by the Illinois Endangered Species Protection Board.
The "Checklist of Illinois Endangered and Threatened Animals and Plants" maintained by the Illinois Endangered Species Protection Board currently lists more than Illinois 350 species as endangered and more than 100 species as threatened in Illinois. The majority of Illinois listed species are plants, but Illinois threatened and endangered species also include fishes, amphibians, reptiles, birds, mammals, mollusks, and arthropods.