The East River is a narrow tidal strait connecting Long Island Sound with the lower Hudson Estuary; the Sound and Estuary both communicate with the New York Bight. Subtidal fluctuations in sea level difference between the ends of the strait which are coherent with baratropic flow through the strait are produced mainly by direct setup in the Sound and Estuary and by sea level fluctuations (primarily wind forced) in the Bight. Approximately 70% of the variance in subtidal sea level difference can be accounted for by the two components of wind stress. The direction of dominant wind forcing (wind stress direction producing maximum response) varies considerably with frequency. Response functions relating sea level difference to wind stress components computed for 128 day series for sea level and winds allow us to interpret the direction of dominant forcing in terms of the relative contributions of direct setup and sea level fluctuations in the Bight.