Technical Summary: The base of the convection zone gives rise to a characteristic periodic signal in the mean multiplet frequencies of modes that penetrate into the radiative interior. This has been used previously to investigate the location and extent of overshoot at the base of the convection zone. Using MDI frequency splittings, we are now able to isolate the corresponding signal coming from different latitudes. This enables us to investigate the latitudinal variation of the base of the convection zone. We aim to constrain the variation with latitude both of the location of the base and of the strength of convective overshoot there.