Eastern red cedar (Juniperus virginiana L.) encroachment on native grassland can rapidly transform the vegetation and ecosystem, but the resulting effect on soil properties has not been comprehensively evaluated. This study examined soil properties at five sites in tallgrass prairie within the Bluestem Hills Major Land Resource Area (MLRA). Two trees were selected per site. Soil sampling was done under the tree canopy, at the canopy edge, and in native grass along a transect at each tree. Vertical profile descriptions of soil morphology were documented for each pedon, and laboratory characterization data were determined for each genetic horizon. Dendrochronological investigations yielded a tree age range of 17 to 56 yr, with a mean of 35 yr. Base cations and pH increased in the surface horizon of soils under the eastern red cedar canopy relative to the canopy edge and prairie soils sampling positions. Field and laboratory characterization indicated that soils under eastern red cedar vegetation still retain many properties of the prairie derived soil; however, some properties related to soil genesis may be more dynamic and can be influenced on a decadal time scale.