The value of the proton hydration free energy, Delta G(hyd)(H+) has been quoted in the literature to be from -252.6 to -262.5 kcal/mol. In this article, we present a theoretical model for calculating the hydration free energy of ions in aqueous solvent and use this model to calculate the proton hydration free energy, Delta G(hyd)(H+), in an effort to resolve the uncertainty concerning its exact value. In the model we define Delta G(hyd)(H+) as the free energy change associated with the following process: Delta G[H+(gas)+ H2nOn(aq)-->H+(H2nOn)(aq)], where the solvent is represented by a neutral n-water cluster embedded in a dielectric continuum and the solvated proton is represented by a protonated n-water cluster also in the continuum. All solvated species are treated as quantum mechanical solutes coupled to a dielectric continuum using a self consistent reaction field cycle. We investigated the behavior of Delta G(hyd)(H+) as the number of explicit waters of hydration is increased from n = 1 to n = 6. As n increases from 1 to 3, the hydration foe energy decreases dramatically. However, for n = 4-6 the hydration foe energy maintains a relatively constant value of -262.23 kcal/mol. These results indicate that the first hydration shell of the proton is composed of at least four water molecules, The constant value of the hydration free energy for n greater than or equal to 4 strongly suggests that the proton hydration free energy is at the far lower end of the range of values that have been proposed in the literature.