The Deccan Peninsula is a vast, ancient geographical concept, representing the entire southern peninsular region of India, south of the Narmada River and the Vindhya-Satpura ranges. The name itself is derived from the Sanskrit word dakshina, meaning "south". It is a type of geographical sub-region, covering an area of approximately 1.9 million km².
The core of the peninsula is the Deccan Plateau, a triangular tableland with an average elevation of about 600 meters. Its origin is deeply rooted in geological history, with the formation of the Deccan Traps—a massive volcanic plateau—beginning around 66 million years ago at the end of the Cretaceous period. This formation was caused by extensive basaltic lava flows, likely associated with the Réunion hotspot, as the Indian Plate drifted northward. The underlying rock consists of granite and sedimentary rocks from the Precambrian era.
The peninsula is framed by the Western Ghats and the Eastern Ghats, which are escarpments that meet at the southern tip of India. The plateau slopes gently from west to east, which dictates the flow of its major perennial river systems, such as the Godavari, Krishna, and Kaveri, all of which flow eastward into the Bay of Bengal. The region connects to the larger concept of the Indian subcontinent and is one of the oldest and most stable land formations within it. The Deccan Traps are a key feature, covering an area of about 500,000 km² and consisting of multiple layers of solidified flood basalt, which is responsible for the region's characteristic black soil.