Townships designated by name are labelled and borders are shown in solid black lines.
Township designations in the Federal Township-Range Survey System are the numbers along the bottom and right side in blue. These townships are indicated by the gray, dashed lines.
Township-Range designations east of the 3rd Principal Meridian are measured from that meridian and it's associated baseline in Southern Illinois. Township-Range designations west of the 3rd Principal Meridian are measured from the 4th Principal Meridian and its baseline in Western Illinois.
[More about the Federal-Towship Range System of Land Survey.]