About 10,000 years ago, around 8000 BCE, Native Americans of the Archaic period occupied rockshelters along the Mississippi River bluffs as well as open-air sites. They hunted, fished, and gathered wild plant resources, moving frequently during the year as they depleted local resources. Some of the most thoroughly studied sites are in the Illinois River Valley.
Around 5000 years ago, Native Americans began cultivating several species of plants, as well as continuing to hunt and collect wild plant foods. Cultivated plants included squash, sunflower, goosefoot, marshelder (sumpweed), and erect knotweed. Because they lived year-round in permanent villages, mostly on river floodplains, they made and used a wider variety of tools than their highly mobile ancestors.
Modoc Rock Shelter
Southeast of Prairie du Rocher in Randolph County, Illinois, Modoc Rock Shelter is a National Historic Landmark that preserves evidence of human habitation during the Archaic Period from 9000 to 4000 years ago. Discovered in 1951 by archaeologist Irwin Peithmann, the site yields artifacts from nearly thirty feet of sediment. It was used as both a short and long term camp over time. Recovered artifacts include bone awls, stone tools, and projectile points. Discarded animal bones show that the inhabitants consumed deer and smaller creatures, birds, and fish.