The relative location of ionospheric parameters and ground magnetic perturbations in the vicinity of the Harang discontinuity is examined. For this purpose, we use combined observations of the Chatanika incoherent scatter radar and of the IMS Alaska meridian chain of magnetometers, which were continuously measuring the crucial ionospheric parameters near the Harang discontinuity when a sizeable substorm took place. The Harang discontinuity, as defined by the reversal of the north-south electric field, is found to be located at 1-2¿ poleward of the discontinuity identified by the conventional method of using ground magnetic perturbations. It is also found that the relative location of auroral conductivity enhancements is quite variable, depending perhaps upon substorm time. During relatively quiet times and the early stage of a substorm, a conductivity enhancement occurs only on the poleward side of the Harang discontinuity defined by the electric field reversal, whereas the enhancement surges equatorward extending beyond the discontinuity during the maximum to recovery phase of a substorm.