Public Land Survey System (PLSS)

Instructions: This web page will allow you to enter an Illinois address and determine its legal description to the section level-of-detail. The Public Land Survey System (PLSS) is used in legal descriptions and employs a grid system described in terms of numbered townships, ranges, and sections. Please follow the instructions below. Note: If the Google Maps application below is not displayed, make sure to enable Javascript on your Internet browser.

  1. Enter your address in the box below and click "Search Address." Address location is provided by Google geolocation service.
  2. Please check that location is accurate. If not, see step 4.
  3. An information window will appear listing the County, Township, Range, and Section for the marker location. Also listed is the Principal Meridian from which that area was surveyed, USGS 7.5-minute Quadrangle name, Civil Township or Precinct name, and Latitude/Longitude coordinates.
  4. If you would like to move the marker due to an incorrect geolocation, first close the information window by clicking on the "X" in the top right corner, then drag the marker to a new location. A new information window will appear with the new location information.

ISGS PLSS Data Explanation

The data set within the Google Maps viewer contains Illinois Public Land Survey System (PLSS) boundaries.

The data were digitized in the late 1960s, early 1970s, and in 1984-85 from 7.5 and 15-minute USGS topographic quadrangles. Errors in the location of a given feature are dependent on the accuracy of the original maps and on the accuracy of digitizing. Estimates are that features have an average locational error of approximately plus/minus 100 feet. Some areas of the state have a locational error of approximately 600 feet.

Major roads have typically been laid out along section boundaries spaced one mile apart. If your location is within 200 feet of a section line, you may want to check the accuracy of the section line using the appropriate USGS topographic map.

In areas of French colonization land grants, where PLSS sections were not actually surveyed, sections and section lines have been added (estimated).

A graphic overview of the township and range system in Illinois is available in ISGS Circular 451.

Supplementary Data from the U.S. Census Bureau

Township and precinct names were obtained from the Census Bureau's 2012 TIGER/Line geospatial data. Civil township/precinct boundaries do not exactly match the PLSS townships and ranges, although in many areas of the state the two systems are coincident.

Township and precinct names are provided as a convenience to the user, yet their designation does not constitute a determination of jurisdictional authority or rights of ownership or entitlement and they are not legal land descriptions. Locations within 200 feet of the civil township boundary may be susceptible to potential digitization errors and should be verified using other means. Plat books or maps may provide the user with more detail, and may be obtained from appropriate county offices and/or non-governmental vendors.


The Illinois State Geological Survey and the University of Illinois make no guarantee, expressed or implied, regarding the correctness of the interpretations presented in this data set and accept no liability for the consequences of decisions made by others on the basis of the information presented here.