Spatial discretization is the cornerstone of all spatially-distributed numerical simulations including watershed hydrology. Traditional square grid spatial discretization inevitably suffers from several drawbacks. In this project, we developed a watershed delineation model using the hexagon grid spatial discretization. We applied this model to different types of watersheds and we evaluated its performance against the traditional method. The comparisons show that results from hexagon grid spatial discretization exhibit many advantages over the tradition method. We suggest spatially distributed hydrological simulation should consider hexagon grid spatial discretization.