The U.S. Geological Survey (USGS), in cooperation with the Harris-Galveston Subsidence District and Fort Bend Subsidence District, constructed a finite-difference numerical groundwater-flow model of the northern Gulf Coast aquifer region for 1897 through 2018 using MODFLOW 6 with the Newton formulation solver to simulate groundwater flow and land-surface subsidence. Model parameter estimation and uncertainty analysis were conducted with PEST++ Iterative Ensemble Smoother software. The simulated results are described in the associated U.S. Geological Survey Professional Paper 1877. The model archive provided in this U.S. Geological Survey data release includes all the necessary files to run the MODFLOW 6 model and process the results for the posterior base realization as displayed in the accompanying report. The readme_v2.txt file describes selected files and directories in the archive and provides instructions for running the model. This 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/pp1877). This data release version 2.0 has been updated from the original version to include additional model outputs. The model inputs are identical to those included in data release version 1.0 and will produce identical results.