We explore the relationship between mid-latitude and synchronous orbit magnetic signatures and the location of the auroral surge at the onset of three isolated magnetospheric substorms. Mid-latitude data come from the Air Force Geophysics Laboratory Magnetometer Network, synchronous orbit data from the satellites GOES 2 and 3, and auroral data from Defense Meteorological Satellite Program auroral images and auroral magnetograms. We find that the surge forms with its western edge ~ 1 hour west of the longitude where the major axis of the mid-latitude Pi 2 polarization ellipse is along magnetic north and where the D component perturbation of the magnetic bay is near zero. These observations are in qualitative agreement with a current wedge consisting of a localized upward current in the west and a longitudinally distributed current in the east. At synchronous orbit the longitude of the surge head appears to separate a region to the west where the magnetic field becomes more taillike from one to the east where the magnetic held becomes more dipolar. ¿American Geophysical Union 1987