The central part of the state lies in the fertile upper basin of the Mahanadi river and its tributaries. This area has extensive rice cultivation. The upper Mahanadi basin is separated from the upper Narmada basin to the west by the Maikal Hills (part of the Satpuras) and from the plains of Odisha to the east by ranges of hills. The southern part of the state lies on the Deccan plateau, in the watershed of the Godavari River and its tributary, the Indravati River. The Mahanadi is the chief river of the state. The other main rivers are Hasdeo (a tributary of Mahanadi), Rihand, Indravati, Jonk, Arpa and Shivnath. It is situated in the east of Madhya Pradesh.