LaPorte County Geology
LaPorte County is located within the glaciated portion of the state and can be divided into three physiographic regions as shown in Figure 8. Physiographic regions are areas of characteristic soils, landforms and drainage that have been developed on geologically similar materials.

Figure 8. The three major physiographic regions in LaPorte County.

The Calumet Lacustrine Plain lies on the border of Lake Michigan and consists of sand dune ridges and wet flat areas. Most soils are formed in eolian, or wind-blown deposits.

The Valparaiso Moraine is higher in elevation than the other parts of the county, and separates the Lake Michigan from the Kankakee watershed. Depressions called “kettle holes” are present along the northern slope of the moraine. Large kettle depressions are now lakes, while small depressions are filled with sediment including peat and muck.

The Kankakee Outwash and Lacustrine Plain is nearly flat, with few natural drainage channels. Before modern drainage, most of this area consisted of wetlands.