Linear viscoelastic parameters were fit to stress relaxation data at ~10% strain, which differed significantly by anatomic region. In the corona radiata, reduced relaxation functions for strains of 10%, 20%, and 30% were not significantly different suggesting that quasilinear viscoelastic theory may be appropriate. In a second set of studies with the atomic force microscope, frequency and depth-dependent moduli were calculated from oscillatory tests in the corona radiata (5-400 Hz). Results from both methods were compared by correspondence principles and were within a factor of 3 of each other. These data, for the first time, describe high rate, large deformation behavior of multiple regions of the porcine brain which will be useful for understanding brain injury biomechanics at a finer spatial resolution than previously possible.