Seamless unconfined groundwater heads for U.S. coastal North and South Carolina groundwater systems were modeled with homogeneous, steady-state MODFLOW simulations. The geographic extent examined was limited primarily to low-elevation (land surface less than approximately 10 m above mean sea level) areas. Steady-state MODFLOW groundwater flow models were used to obtain detailed (50-meter-scale) predictions over large geographic scales (100s of kilometers) of groundwater heads for both current and future sea-level rise (SLR) scenarios (0, 0.25, 0.5, 1, 1.5, 2, 2.5, and 3 m) using 3 spatially varying hydraulic conductivities (K); one based on published K’s, one with published K’s reduced by a factor of 10 (K0.1), and one with published K’s increased by a factor of 10 (K10) to assess the sensitivity of model results to K. All models had variable thicknesses corresponding to published transmissivities. The models were run with a local mean higher-high water (MHHW) marine boundary condition and with groundwater reaching the land surface removed from the model, simulating loss via natural drainage.