Purpose: The anatomy of the mandible was examined by measuring the cross-sectional area (CSA) of multiple regions of 10 fully dentulous hemimandibles to provide a better understanding of regional structural differences that may have implications regarding biomechanical strength, surgical reconstruction, and fracture site frequency. Materials and Methods: Fifteen cuts from the condyle to the symphysis were made of each hemimandible (n = 150 cuts). A Zeiss Videoplan digitizer was used to determine the CSA. Results: The total CSA through the condyle was greater than the CSA through the condylar neck. The CSA through the ramus exceeded that of the condylar neck. The total CSA of the midramus was significantly greater than that of the upper ramus. The total CSA at the body, parasymphysis, and symphysis was significantly greater than at the mid-angle. The total CSA of the cortex increased anteriorly; these differences become significant between the condylar neck and the body, parasymphysis, and symphysis. The total CSA, and the CSA of the cortex and spongiosa, remained relatively constant from the inferior angle anteriorly. Conclusions: Significant differences exist in the CSA at different points, with an increase in the total, cortical, and spongiosal CSA anteriorly from the condylar neck to the angle. The total CSA and the CSA of the cortex and spongiosa remain relatively constant anterior to the inferior angle. These data suggest that bony CSA alone is not the sole factor in determining fracture site frequency.