The Illinois was a large prairie cut by many streams and rivers, with forests in the northwest and south. There were few roads. Travellers has to take a water route or hack their way through thick brush or head-high grasses.
Early settlers and travelers described the land of Illinois in their journals and letters. For example, in 1710 Antoine Denis Raudot wrote about the land, plants, trees, and animals in the country the Illinois Indians inhabited.
The far northwestern corner and the far southern part of the Illinois Country was hilly terrain covered in forests. Much of the rest of the future state was prairie land with small groves of trees. There were many rivers and tributary streams and many were lined with gallery forests. The prairie was a source of wonder for the Europeans and Euro-American settlers.
Native Americans managed the prairie with annual fires associated with hunting. The fires kept the forest from encroaching on the prairie.
The Illinois Country was rich in animal life, too. Lewis and Clark mentioned many mammal, bird, fish, and insect species in their journals. This section of the Web site contains a photo gallery of images of plants and animals from the Illinois State Museum Collection.
See our Gallery images of herbarium sheets of prairie and forest plants mentioned by Lewis and Clark in their journals.