This data release contains three groundwater-flow models of northeastern Wisconsin, USA, that were developed with differing levels of complexity to provide a framework for subsequent evaluations of the effects of process-based model complexity on estimates of groundwater age distributions for withdrawal wells and streams. Preliminary assessments, which focused on the effects of model complexity on simulated water levels in the glacial aquifer system, illustrate that simulation of vertical gradients using multiple model layers improves simulated heads more in relatively low-permeability units than in high-permeability units. Moreover, simulation of heterogeneous hydraulic conductivity fields in both coarse-grained and some fine-grained glacial materials produced an even larger improvement in simulated water levels in the glacial aquifer system compared with simulation of uniform hydraulic conductivity within zones. Future application of the models using simulated particle tracking is anticipated to evaluate whether these model design considerations are similarly important for understanding groundwater age distributions. This work was performed as part of the National Water Quality Assessment (NAWQA) Project's groundwater Mapping and Modeling work plan to evaluate effects of differing levels of model complexity on simulated results. The models were calibrated to approximately the 1970-2012 period, and used to simulate steady-state conditions. This USGS data release contains all of the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20175010). This data release also includes a postprocessing python script and associated input data files for creating shapefiles used to produce maps of head and flux residuals and comparisons of these residuals (figures 12, 13, and 19 in the report).