The Chickasaw Nation lies within the region, with the tribal capitol building located at Tishomingo and its headquarters in Ada.
It also contains a large portion of the Cross Timbers region, transitioning from a heavily wooded area (with native oaks, elms and other eastern varieties) to a rolling savanna in the west, occasionally broken by cedar and mesquite trees.
[5] The Arbuckle Mountains are the defining geographical entity in this region, with peaks (once taller than the Rockies) eroded down to their current elevation of 200-300' above the surrounding terrain.
Other draws in the region include Oklahoma's tallest waterfall, Turner Falls, as well as the restored historic downtowns of Ardmore, Durant and Ada.
The growth of the southern portion of the region rivals that of both the Oklahoma City and the Tulsa metropolitan regions, with Bryan and Marshall counties (areas surrounding Lake Texoma) adding greater numbers of residents due to the explosive northward growth in the Dallas/Fort Worth Metroplex.