Recent seismic reflection observations have shown a considerable shortening of the Sudbury Structure in a direction roughly perpendicular to its long axis. Using a kinematic reconstruction technique for gridded geophysical data, which takes into account non-uniformly distributed strain, we reconstruct the pre-deformation shape of the Sudbury Structure and show that it could have been circular at the time of its formation (~1.85 Ga). This supports an impact origin. ¿ American Geophysical Union 1994