The response of the magnetosphere to the passage of the January 10--11, 1997 coronal mass ejection (CME) is described from the vantage point of geosynchronous orbit. Salient aspects of the observed response include 1) the global compression of the magnetosphere, including plasma sheet density enhancements and geosynchronous magnetopause crossings; 2) strongly stretched magnetotail field, with attendant substorm activity; 3) enhanced magnetospheric convection, leading to plasmaspheric erosion and dayside drainage; 4) no detectable superdense plasma sheet; and 5) propagating plasma-sheet density fronts. The various aspects are related to the variations in the solar wind and interplanetary magnetic field impinging on the magnetosphere. ¿ 1998 American Geophysical Union