60 ILCS 1/5-35
The commissioners shall proceed to divide the county into townships, making them conform to the townships according to government surveys. Fractional townships may be attached to adjoining townships if the number of the inhabitants or the amount of territory of a fractional township is not sufficient for a separate township. If a township has too few inhabitants for a separate organization, then the township may be added to some adjoining township or divided between 2 or more townships for the time being. When a creek or river so divides a township that it is inconvenient for transacting township business, the creek or river may be made the township boundary, and the fractions so formed may be disposed of as other fractional townships.
60 ILCS 1/5-35