How Well Locations Are Described in Illinois
ISGS Well Database Access
In 1785, a rectangular system of land survey, commonly referred to as the township and range system, was adopted for dividing all newly settled territory of the United States. The township and range system permits the accurate identification of most parcels of land in Illinois. In the early 1800s each normal township was divided to the best of the surveyor's ability into 36 sections, each section being 1 mile square and containing 640 acres. For the purpose of locating wells, each section can be subdivided into halves, quarters, quarter-quarters, and even quarter-quarter-quarters. Footages measured from a corner or a line are required to further pinpoint the exact spot for a well site.
Each section is divided into quarters and referred to as NE, NW, SE, SW. Each quarter is then divided into four quarters and referred to as NE NE, NW NE, SE NE, SW NE and so on. Each quarter-quarter is then divided into 4 quarters and referred to as NE NE NE, NW NE NE, SE NE NE, SW NE NE and so on. Note that the first quarter given in the description is the smallest quarter division. For example, SW NE SE means the southwest quarter of the northeast quarter of the southeast quarter of the section.
When footages are given to pinpoint a well location, they must have a reference corner or line. A corner of a section or a corner of a specific quarter may be used or a north or south line and an east or west line. For example, 330'N and 330'E of the SW/c of the NE NE means the spot is 330 feet north, 330 feet east from the southwest corner of the northeast quarter of the northeast quarter. Another way to describe the same spot is 330'SL, 330'WL of NE NE which means 330 feet from the south line, 330 feet from the west line of the northeast quarter of the northeast quarter.
Updated 02/09/2012 ABL