Observations of postseismic deformation generally suggest that the effects of postseismic viscoelastic relaxation may persist for many decades after an earthquake. In particular, strain effects from the three great earthquakes that occurred in the New Madrid seismic zone in 1811-1812 may influence present day measurements of ground deformation in this active seismic region of the central United States. Forward calculations using an earth rheology that may be appropriate for a continental intraplate region and a simple fault model for the 1811-1812 sequence suggest that postseismic relaxation may be an important factor in driving the unexpectedly high rate of shear deformation recently observed in the southern New Madrid Seismic Zone. ¿ American Geophysical Union 1994