An experimental study of the influence of gold nanoparticles on a alpha-Fe2O3 photoanodes for photoelectrochemical water splitting is described. A relative enhancement in the water splitting efficiency at photon frequencies corresponding to the plasmon resonance in gold was observed. This relative enhancement was observed only for electrode geometries with metal particles that were localized at the semiconductor-electrolyte interface consistent with the observation that minority carrier transport to the electrolyte is the most significant impediment to achieving high efficiencies in this system.