1800
to 1876
This period begins with the permanent settlement of towns along the Illinois River, particularly from Peoria south to Grafton and ends with the establishment of the Illinois Laboratory of Natural History and the beginning of the collection of scientific data. This period is one of dramatic population growth, the enormous expansion of industry along the Illinois, and a decline in water quality, although not documented scientifically. Anecdotal accounts are available to infer conditions within and adjacent to the river.
