The Chota Nagpur Plateau is a plateau in eastern India, which covers much of Jharkhand state as well as adjacent parts of Chhattisgarh, Odisha, West Bengal and Bihar. The Indo-Gangetic plain lies to the north and east of the plateau, and the basin of the Mahanadi river lies to the south. The total area of the Chota Nagpur Plateau is approximately . Etymology The name Nagpur is probably taken from Nagavanshis, who ruled in this part of the country. Chhota (small in Hindi) is the misunderstood name of "Chuita" village in the outskirts of Ranchi, which has the remains of an old fort belonging to the Nagavanshis. Formation The Chota Nagpur Plateau is a continental plateau—an extensive area of land thrust above the general land. The plateau has been formed by continental uplift from forces acting deep inside the earth. The Gondwana substrates attest to the plateau's ancient origin. It is part of the Deccan Plate, which broke free from the southern continent during the Cretaceous to embark on a 50-million-year journey that was interrupted by the collision with the Eurasian continent. The northeastern part of the Deccan Plateau, where this ecoregion sits, was the first area of contact with Eurasia. Divisions The Chota Nagpur Plateau consists of three steps. The highest step is in the western part of the plateau, where pats as a plateau is locally called, are above sea level. The highest point is . The next part contains larger portions of the old Ranchi and Hazaribagh districts and some parts of old Palamu district, before these were broken up into smaller administrative units. The general height is . The topography in undulating with prominent gneissic hills, often dome-like in outline. The lowest step of the plateau is at an average level of around . It covers the old Manbhum and Singhbhum districts. High hills are a striking part of this section – Parasnath Hills rise to a height of and Dalma Hills to . The large plateau is subdivided into several small plateaus or sub-plateaus. Pat region The western plateau with an average elevation of above mean sea level merges into the plateau of the Surguja district of Chhattisgarh. The flat topped plateau, locally known as pats are characterized by level surface and accordance of their summit levels shows they are part of one large plateau. Examples include Netarhat Pat, Jamira Pat, Khamar Pat, Rudni Pat