Illinois Archaeological Predictive Model

Illinois Archaeological Predictive Model (IAPM)

An archaeological service from the Prairie Research Institute to the citizens of Illinois

The Illinois Archaeological Predictive Model (IAPM) is a GIS-based tool developed by the Illinois State Archaeological Survey (ISAS), part of the Prairie Research Institute at the University of Illinois Urbana-Champaign. The model builds on over a century of archaeological work in Illinois, and considers the known locations of prehistoric Native American sites, landforms that lack archaeological sites, and other environmental and geophysical variables such as elevation, distance to rivers and streams, and native vegetation. Data sampled from these locations are analyzed via GIS (Geographic Information Systems) and fed into a TensorFlow neural network (a machine learning algorithm) to predict the probability of encountering an archaeological site in every two acre square (90 x 90 meter cells) across the state.

ISAS and other interested stakeholders use the IAPM to help protect, preserve, and assess the potential impact to irreplaceable and non-renewable archaeological resources within the context of Illinois' need to encourage and promote sustainable development. Using the IAPM helps archaeologists prioritize time and resources during surveys, and allows us to make recommendations that prevent or mitigate impacts to the archaeological record. It also has the potential to enable ordinary citizens, managers, developers, and preservationists to become proactive planners when it comes to the archaeological resources of Illinois.

Interested? Go to or click on the image below to explore the Illinois Archaeological Predictive Model.

ISAS also offers further consultation on the results of the IAPM as they relate to your project or area of interest. This is a free service offered by ISAS for landowners, developers, and fellow archaeologists. Requests for consultation are for informational and planning purposes only, and will have no bearing on the Illinois State Historic Preservation Office (SHPO) determination of whether archaeological survey will be required. Requests can be submitted by using the web form located at

Please allow up to two weeks for a response. Once you receive your IAPM report, please direct questions to We are happy to provide more information about the model or help interpret the results as they relate to your project. Questions about consultation with the Illinois SHPO should be directed to the state’s Chief Archaeologist, Jeff Kruchten at

The Illinois Archaeological Predictive Model (IAPM) predicts the probabiilty of encountering an archaeological site in each 90x90 m cell across the state. Probability values are on a continuous scale between 0.0 (blue) and 1.0 (red).

  1. Navigate to your area of interest by clicking My Location, searching for an address or place, or entering a set of coordinates.
  2. Use the Layer List to turn reference layers or the site probability layer on/off.
  3. Use the Add Data button to insert layers from ArcGIS Online, an URL, or an external file (zipped shp, csv, kml, gpx, or GeoJSON).
  4. Click the Legend to see symbology for all active layers.
  5. You can also use the Measurement or Draw tools to explore areas and mark features of interest.
  6. The Print button automatically generates a map layout that includes a title, scale bar, legend, and copyright info. After selecting page layout and export format, click Print, then click your file in the list to download.

For help using the IAPM viewer, email the Illinois State Archaeological Survey at

Data in the IAPM web viewer, including predicted site probability, predicted erosion hazard, and development intensity are distributed under a CC-BY-NC-SA license (Attribution-NonCommercial-ShareAlike 4.0).