 The Ouachita Mountains are in the eastern part of the county, while the Sandstone Hills and Coastal Plains physiographic regions provide a more level terrain suitable for agriculture in the north and western part of the county.About 12 miles WSW of the town of Atoka is Boggy Depot State Park, the historic site of a once large community on the Butterfield Overland Mail stagecoach route.The Katian Age of the Ordovician Period of geological time is named for Katy Lake which is 2 miles north east of Atoka.