In this study, we determined the carbon balance in the Great Dismal Swamp, a large forested peatland in the southeastern USA, which has been drained for over two hundred years and now is being restored through hydrologic management. We modeled future net ecosystem carbon balance over 100 years (2012 to 2112) using in situ field observations paired with simulations of water-table depth. The three scenarios used in the model were baseline conditions, flooded/wet conditions, and drained/dry conditions, which represent a range of potential management actions and climate conditions at the Great Dismal Swamp. This U.S. Geological Survey Data Release provides the modeled output estimating the net ecosystem carbon balance, on an annual time-step, from 2012 through 2112, for each scenario. The U.S. Geological Survey modeling framework is referred to as the Land Use and Carbon Scenario Simulator (LUCAS), which uses a state-and-transition simulation model coupled with a carbon stock-flow model. The model operates within an open source software environment (SyncroSim) to annually track changes in vegetation (i.e., cedar, maple-gum and pine-pocosin) and their corresponding carbon stocks. The modeled output for each scenario is provided in a tabular format (csv).