Hypothetical two-dimensional, steady-state groundwater flow models of a previously published 1988 model calibration exercise were developed using the finite-difference computer code, MODFLOW-2005, to demonstrate the power of modern parameter estimation and uncertainty approaches. For this study, an initial run recreated the 1988 "truth" model. The true model was then simplified to account for information not provided the participants in the 1988 calibration exercise. Increasing sophistication was brought to bear to demonstrate how problems identified in 1988 were overcome using modern software approaches. This USGS data release contains all of the input and output to run the model simulations described in the associated journal article (https://doi.org/10.1111/gwat.12907).