On the basis of the simultaneous observations of field-aligned currents by the Triad satellite and auroras by the Alaska meridian all-sky cameras, it is shown that (1) in the evening sector, discrete arcs are, in general, confined within the region of the upward field-aligned current and (2) the region of the diffuse aurora, located equatorward of discrete auroras, appears to correspond to the region of the downward field-aligned current.