The Boston Mountains area is a high and deeply dissected plateau. They are located in northern Arkansas and eastern Oklahoma. The Oklahoma portion of the range is locally called the Cookson Hills. The rocks of the region are sedimentary layers of the Paleozoic age. The highest ridges and peaks are capped by Pennsylvanian sandstone and shale. The deeply eroded valleys are cut into Mississippian limestones and below that layer Ordovician dolomites.