Williams County, in northwestern North Dakota, is located near the center of the structural and sedimentary Williston basin. The preglacial sedimentary formations beneath the county are as much as 14,828 feet thick. Their beds dip generally to the south except along the flanks of the north-south striking Nesson anticline in the eastern part of the county. Late Wisconsinan glacial deposits cover all of Williams County except along the Missouri River and other scattered small areas.