This paper proposes algorithms to automatically discretize vehicle routing zones (VRZ) from continuum approximation guidelines. VRZs that satisfy these guidelines (i.e., shape and size requirements) are useful to the planning and operation of distribution systems in several practical contexts. In the literature, however, VRZ design normally requires human intervention, and this is inconvenient and time-consuming especially for large-scale and complex systems. This study fills this gap by utilizing a combination of spatial partitioning techniques to systematically obtain optimum zone designs. Numerical examples show that the proposed algorithm yields satisfying outcomes.