Illinois

State Route 255 in Illinois SR-255 Get started Pontoon Beach End Godfrey Length 23 mi Length 38 km Route 02 poag 3 New Poag Road 5 South Roxana 6 Roxana 8 Wood River 10 Bethalto 13 Fosterburg 16 Alton 19

Archaeologists are not sure exactly when the first humans arrived in what is now Illinois. But archaeologists have unearthed ancient spearheads and tools suggesting that people lived here at least 10,000 years ago. The first known Indian tribes of Illinois,