Traffic pans and naturally occurring strong subsoil are common in the wheat-belt of Western Australia. Granite and sandy sediments are the dominate parent materials and lateritic profiles have developed from in situ isovolumetric chemical and physical weathering. These profiles may be truncated and soils with traffic pans and strong subsoil form within the truncated profiles or their erosional products. Identifying a range of strengths for strong soils that restrict plant root growth will assist in the field recognition of these soils, thus enabling appropriate ripping strategies to be applied. The occurrence and distribution of strong soil can then be mapped using the existing soil mapping database. Intact clods from traffic pans and strong subsoils at 15 sites within the wheatbelt were cut into cubes (8 cm3), equilibrated at 7 matric potentials and then subjected to unconfined compression strength measurements to quantify strength. Scanning electron microscopy was used to examine the fabric arrangement. Strength increases from field capacity (-10 kPa) to permanent wilting point (-1500 kPa) and ranges from 24 to 698 kN/m2 at -1500 kPa. Naturally occurring strong subsoil is considerably stronger than traffic pans for a given matric potential which may be due to a matrix support fabric. Weak traffic pans and subsoil generally have a grain supported matrix. Electron microprobe analysis of clay coatings and clay particles indicates that amorphorous silica may act as a cementing agent which increases soil strength. Ripping may fracture traffic pans and strong subsoil, thus allowing plant roots to access the soil below the pan, but the optimum moisture content for ripping a particular strong soil needs to be quantified. Further investigation is required to develop a protocol for mapping soil strength using the existing soil mapping database for the wheatbelt soils.