Rivers and streams meander extensively through this region. The few lakes are shallow and perched. Sheet flooding is common each spring. The Hardwood Hills is in the transition zone from prairie to woods. Steep slopes, hills and lakes formed in glacial end moraines, outwash plains characterize this unit.
Soils range from loamy sands and sandy loams on outwash plains to loams and clay loams on moraines.
The Anoka Sand Plain is a flat, sandy lake plain along the Mississippi River. Recent mapping suggests that much of the sand plain, once thought to be fluvial, is probably lacustrine in origin. The soils are primarily fine sands with organic and loamy hydric soils in depressions. Glacial till is deposited in scattered moraines. The regional water table is very shallow, usually less than 15 feet below the surface with many exposures as wetlands, lakes, and streams.