These soils have a finer textured argillic horizon. Thetford soils are in nearly level or depressional areas in moraines, till plains, lake plains, outwash plains, terraces, and beach ridges of Wisconsinan Age materials. Slope gradients are predominantly 0 to 2 percent but range from 0 to 4 percent. The poorly or very poorly drained Granby series is associated in some areas. Somewhat poorly drained.
Permeability is moderately rapid.
Thetford soils are cultivated in most areas. Corn, soybeans, wheat, oats, and grass-legume hay are the principal crops. Some areas are idle or used for permanent pasture. Native vegetation was principally mixed hardwoods, with northern red oak, bitternut hickory, red maple, and American elm the dominant species. The series is of large extent.