Improvements to an existing regional groundwater-flow model of a 160-square mile area of coastal New Hampshire (https://doi.org/10.3133/sir20085222), incorporating MODFLOW-NWT and by more accurately representing stream characteristics, were presented at the MODFLOW and More 2017 conference in an example simulating approximate changes in water use. The groundwater-flow model developed for the previous study incorporated detailed water-use information for 2003-04 and simulated the effects of projected increases in water use. At that time, population growth and increasing water demand prompted concern for the sustainability of the region’s groundwater resources in a fractured-crystalline bedrock-aquifer with little storage. However, poor stream representation may reduce the effectiveness of the heads simulated by the original model. Groundwater heads in an area of relatively large population change, near the center of the Seacoast’s fractured bedrock aquifer, were simulated with the upgraded model using published 2004 and approximated 2015 water-use rates. This USGS data release contains all the input and output files for the simulations described in the associated proceedings paper from the MODFLOW and More 2017 conference. The publication which documents this work is included in the ancillary directory of this data release.