Some isolated linear mountain ridges rise to nearly 1,500 m above sea level. The area is highly diversified. It consists of many parallel ridges, narrow intervening valleys, and large bodies of low, irregular hills. The ridges and valleys often have a difference in elevation of 200 m. The western side of the area is dominantly hilly to very steep and is rougher and much steeper than the eastern side, much of which is rolling and hilly.
Maximum precipitation is in midwinter and in midsummer, and the minimum is in autumn.
Precipitation generally is adequate for crops and for other needs. Short dry periods early in summer occasionally reduce crop yields. Permanent streams, originating in the mountainous regions on either side, carry water to nearly all parts of the area. Several dams, constructed by the Tennessee Valley Authority on the Tennessee River and its major tributaries, provide flood control, navigation, power production, and recreation. Shallow wells, supplemented locally by springs and ponds, are important sources of water for farmstead use.