A steady-state groundwater flow model was developed for watersheds on the north shore of Long Island Sound in coastal Connecticut and adjacent areas of New York and Rhode Island. As part of the analysis, groundwater travel times and the components of the groundwater budget were calculated for each HUC12 basin within the model domain and for the watersheds of selected embayments identified by the Connecticut Department of Energy and Environmental Protection. The seaward boundaries of the HUC12 basins were extended to include adjacent coastal waters. This compilation includes shapefiles of the HUC12 basins and of the watersheds of selected embayments. Shapefiles of the selected embayments without the corresponding watersheds have also been included. The shapefiles include key simulated groundwater budgets and travel time values. The compilation also includes csv files with the complete groundwater budget and all computed travel time statistics for each extended HUC12 basin and for the watershed of each selected embayment, as well as csv files that were used in model development (StreamWidthData.csv,BaseflowRechargeData.csv, and StreamElevationObservations.csv). Embayment watersheds and HUC12 basins were delineated separately such that there are minor differences in simulated travel times and groundwater budgets for HUC12 basins and embayment watersheds for similar areas due to minor boundary differences, particularly the seaward boundary. Complete model inputs and outputs are available in the model archive accessible at https://doi.org/10.5066/P9BLHPIT.