Soils in Cook County, Illinois

Cook County, Illinois is home to 5,194,625 residents. Land Owl's soils layer records the following within the county boundary — Well-drained land: 45,446 acres. Share of mapped soil that is well drained: 7.4%. Poorly drained land: 153,232 acres. Most common drainage class: Moderately well drained — 197,765 acres. Distinct soil map units: 161. Largest soil map unit: Urban land — 103,827 acres. Share with hydrologic soil group A or B (high infiltration): 2.6%. Typical shallowest annual water table: 28 in below the surface. Every feature shown on the map above is clickable, and the figures on this page are derived from the same data the map renders, so they always agree. A free Land Owl account adds parcel boundaries, ownership records, flood zones, wetlands and topography over the same view.

Frequently asked questions

What are the soils like in Cook County, Illinois?

The USDA soil survey maps 45,446 acres of Cook County, Illinois as well drained and 153,232 acres as poorly drained. Drainage class and hydrologic soil group are the two properties that most often decide whether a rural lot can take a septic system and a driveway.

Is this soil map free to use?

Yes. This map is free to view. A free Land Owl account unlocks the other data layers, parcel boundaries and ownership records.

Where does this data come from?

Land Owl maps soils from the USDA Natural Resources Conservation Service SSURGO soil survey. SSURGO describes soil MAP UNITS at survey scale — it is a screening tool for shortlisting land, not a substitute for a site-specific soil evaluation or a septic percolation test, both of which your health department will want before it permits a system.

Can I use this soil map to tell whether land will perc?

It is the right place to start and the wrong place to finish. Drainage class and hydrologic soil group tell you which parcels are worth a site visit, but a health department permits a septic system on a percolation test dug on the actual lot, not on the survey.