Abstract Large-scale (< 1 m) variability in hydraulic conductivity usually is the main influence on field-scale groundwater flow patterns and dispersive transport. Incorporating realistic hydraulic conductivity heterogeneity into flow and transport models is paramount to accurate simulations, particularly for contaminant migration. Sediment lithologic descriptions and geophysical logs typically offer finer spatial resolution, and therefore more potential information about site-scale heterogeneity, than other site characterization data. In this study, a technique for generating a heterogeneous, three-dimensional hydraulic conductivity field from sediment lithologic descriptions is presented. The approach involves creating a three-dimensional, fine-scale representation of mud (silt + clay) percentage using a "stratified" interpolation algorithm. Mud percentage then is translated into horizontal and vertical conductivity using direct correlations derived from measured data and inverse groundwater flow modeling. Lastly, the fine-scale conductivity fields are averaged to create a coarser grid for use in groundwater flow and transport modeling. The approach is demonstrated using a finite-element groundwater flow model of a Savannah River Site solid radioactive and hazardous waste burial ground. Hydrostratigraphic units in the area consist of fluvial, deltaic and shallow marine sand, mud and calcareous sediments that exhibit abrupt facies changes over short distances. For this application, the technique improves estimates of large-scale flow patterns and dispersive transport. The conductivity fields mimic actual lithologic data, providing a more realistic picture of subsurface heterogeneity. Field-observed preferential pathways for contaminant migration are replicated in the simulations without the need to artificially create zones of high conductivity.