San Gorgonio Pass in southern California is a relatively narrow restraining bend at the eastern end of the Big Bend of the San Andreas fault. Gravity and magnetic data define intertonguing thrust wedges that form the upper crust in this region. Tectonic wedging occurred most likely because of transpression caused by space problems within the restraining bend in San Gorgonio Pass. Average rates of convergence implied by this offset are broadly consistent with estimates of convergence from other geologic and geodetic studies. Rates of uplift implied by this offset, however, are almost an order of magnitude greater than those obtained from thermochronometric studies in the area, but this discrepancy may highlight the role of isostatic subsidence in this area. This interpretation suggests that various strands of the San Andreas fault mapped at the surface evolved in not only map but also cross sectional view. Given this multi-layered nature of deformation, it is unlikely that the San Andreas Fault will rupture cleanly through the complex structures in San Gorgonio Pass.