The cross sections for electron scattering on OH-(H2O)(n) for n=0-4 were measured from threshold to approximate to50 eV. All detachment cross sections were found to follow the classical prediction given earlier [Phys. Rev. Lett. 74, 892 (1995)] with a threshold energy for electron-impact detachment that increased upon sequential hydration, yielding values in the range from 4.5 eV+/-0.2 eV for OH- to 12.10 eV+/-0.5 eV for OH-(H2O)(4). For ngreater than or equal to1, we found that approximate to80% of the total reaction events lead to electron detachment plus total dissociation of the clusters into the constituent molecules of OH and H2O. Finally, we observed resonances in the cross sections for OH-(H2O)(3) and for OH-(H2O)(4). The resonances were located at approximate to15 eV and were ascribed to the formation of dianions in excited states. (C) 2004 American Institute of Physics.