Partitioning atomic and molecular charge densities in non-overlapping chemically significant regions is a challenging problem for quantum chemists. The present method aims to build a tool that enables the determination of “good boundaries” with the help of elementary statistical methods or information theory. This is done by minimizing an objective function with respect to the boundaries of the localization regions, the choice of this function being guided by a clarity requirement. With the sum of the indices of dispersion (Σ D) or the mutual information as the objective function, the method yields partitions in good agreement with the Aufbau rules for Li–Rn atoms and with Lewis’s pairing model for molecules.