Historic Landcover

Restoring the historic landcover could increase the amount of carbon stored in Illinois ecosystems.
Restoring the historic landcover would reach the goal of conserving 30% of nature in the state. If all of the historic vegetation were restored and conserved, Illinois would exceed the goal of conserving 30 x 30.

Before today’s familiar landscape of farms, towns and cities, most of Illinois was covered by prairie, forests and wetlands. Survey records from the 1800s show the landscape of Illinois around the time that European-Americans established towns and farms throughout the state. You can explore the historic landscape of Illinois in the map below.

We can think of the historic landscape as a reference point for imagining the potential for conservation and sequestration.

The historic landcover of Illinois would exceed the 30 x 30 goal. It would also sequester more than 10 million tons of carbon per year.

The Landscape of Illinois in the early 1800s

Map: Historic Landcover
Use the slider to see historic and current landcover; historic landcover is shown on the left. You may pan, zoom, turn layers on and off, and click areas to see detailed data.

This map shows the extent of prairies, forests and wetlands in Illinois in the early 1800s. The map is based on records from the Public Land Survey System, a federal program that created plat maps throughout the United States. Surveys recorded ecological features that were seen on the landscape in the early 1800s. This Illinois Natural History Survey compiled data from the original maps and notebooks, then published the historic data in 2003. This dataset is the foundation of the map shown above.

Historical data can be difficult to compare to contemporary data. The surveyors in the 1800s used different methodologies and landcover categories than ecologists use today. This is most apparent in the data about wetlands. In the 1800s, wetlands could be called many different things including: bottomland swamp, marsh, other wetlands, slough, wet prairie. We classified historic bottomland swamps to woody wetlands; we classified historic marshes, other wetlands, sloughs and wet prairies as herbaceous wetlands.