Fossils found in Illinois
The Paleobiology Database records 332 fossil occurrences of 151 genera in Illinois, United States. Every fossil site is shown on the map; colours show the main group found there. States are as recorded by the Paleobiology Database for each fossil collection.
Dots are fossil collections in the Paleobiology Database on today’s map, merged where closer than about 5 km. See them on the ancient Earth →
What fossils have been found in Illinois?
The genera with the most fossil records in Illinois include Castoroides, Platygonus, Calymene, Megalonyx, Cygnus, Castor.
Prehistoric birds (14 genera)
Cygnus, Numenius, Pelecanus, Corvus, Antigone, Aquila, Haliaeetus, Limosa, Tympanuchus, Conuropsis · 4 more genera recorded.
Early tetrapods & amphibians (10 genera)
Amphibamus, Diplocaulus, Phlegethontia, Isodectes · 6 more genera recorded.
Pre-mammals (synapsids) (2 genera)
2 more genera recorded.
Ice Age & later mammals (23 genera)
Castoroides, Platygonus, Megalonyx, Castor, Bison, Marmota, Sylvilagus, Geomys, Cervalces, Bootherium, Equus, Mammut, Procyon, Sorex, Blarina, Lasiopodomys, Euceratherium, Anomodon · 5 more genera recorded.
Ancient fish & sharks (23 genera)
23 more genera recorded.
Ammonites & nautiloids (9 genera)
9 more genera recorded.
Trilobites & sea scorpions (65 genera)
Calymene · 64 more genera recorded.
Giant insects & arthropods (5 genera)
Oligotypus · 4 more genera recorded.
Fossil occurrences: Paleobiology Database (CC0 as reported by the API; CC BY 4.0 policy), downloaded 23 October 2026. Genus pages quote Wikipedia (CC BY-SA 4.0).