river in central India, rising in the Gawilgarh Hills of the central Deccan plateau in south-central Madhya Pradesh state. It flows westward between two spurs of the Satpura Range, across the Jalgaon plateau region in Maharashtra state, and through the plain of Surat in Gujarat state to the Gulf of Khambhat (Khambhat, Gulf of) (an inlet of the Arabian Sea). It has a total length of about 435 miles (700 km) and drains an area of 25,200 square miles (65,300 square km). For the last 32 miles (51 km) it is tidal but is navigable by small vessels. The port of Swally Hole, at the river's mouth, well known in Anglo-Portuguese colonial history, is now deserted, having become silted up. The Tapti flows roughly parallel to the longer Narmada River to the north, from which it is separated by the main part of the Satpura Range. The two river valleys and the intervening range form the natural barrier between northern and peninsular India. The Tapti River's three major tributaries—the Purna, Girna, and Panjhra—flow from the south in Maharashtra state.