Dunham soils formed in 24 to 50 inches of loess or other silty material and in the underlying loamy outwash over sandy and gravelly deposits. The associated soils are on higher positions on the landform. The somewhat poorly drained Grundelein and well drained Waupecan soils form a drainage sequence with Dunham soils. The well drained Bowes and Rush soils and somewhat poorly drained Millstream soils do not have mollic epipedons. The potential for surface runoff is negligible.
Permeability is moderate in the solum and very rapid in the underlying material.
In drained conditions an apparent high water table is at 0.5 foot above the surface to 1 feet below the surface in most years and in undrained conditions 0.5 foot above the surface to 0.5 foot below the surface. Most areas are used to grow corn and soybeans. Some areas are used for growing small grain or meadow. Native vegetation is hydrophitic grasses, reeds, and sedges. The extent is moderate.