The U.S. Geological Survey developed two steady-state finite-difference regional groundwater-flow models using the MODFLOW-NWT computer code. These models simulate flow in the area of historical iron mining on and around the portion of the Mesabi Iron Range that is in the St. Louis River basin in northeastern Minnesota. The models are composed of 8 layers each; the upper four representing unconsolidated glacial sediments and the lower 4 representing bedrock. Horizontal boundary flows for these models are the results of a 2-dimensional analytic element groundwater-flow model of the entire St. Louis River Basin documented here: https://doi.org/10.3133/sir20195033 and available here: https://doi.org/10.5066/P9KUJ0L3. This archive contains two simulations. The mining model simulates groundwater flow under current iron-mining land use, being calibrated to average hydrologic conditions during calendar years 1995-2015. The premining simulation is identical to the mining simulation except that all iron-mining features are removed. It represents a scenario where modern conditions exist but iron mining does not. The models were used to explore the effects of modern iron mining on hydrology in the St. Louis River basin. 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/sir20225124).