 The Holocene peat model, HPM, is a dynamic simulation model designed to study the interactions between peatland carbon and water cycling over decades to millennia. It accounts for the effects of peat depth, water table depth, and vegetation community composition on peat accumulation, which is determined by the balance between above and below ground productivity in litter slash peat decomposition. The model also takes into consideration the effects of peat bulk density on the water balance, which influences the growth rate of the peat column and the capacity to shed water. The model's outputs include time series of annual carbon and water fluxes, peat height, and water table depth, as well as a final peat profile that can be cored and compared to field observations of peat age and macrofossil composition. This article was authored by S. Froking and T. Rulet, E. Tuidola, and others.