The Mithi River is a river on Salsette Island, the island of the city of Mumbai, India. It is a confluence of tail-water discharges of the Powai and Vihar lakes. The river is seasonal and rises during the monsoons. The overflowing lakes also contribute to the river flow, which is stopped by a dam at other times. During this season, the gutter is a favourite with anglers, who can catch large fish that have escaped from the lakes. Chattrapati Shivaji Maharaj International Airport is located right next to the section of river at Andheri (E).

Salsette Island is an island in Konkan division of the state of Maharashtra, along India's west coast. Administratively known as Greater Mumbai, the Mumbai Suburban district, Mira Bhayander and a portion of Thane district lie within it, making it very populous and one of the most densely populated islands in the world. It has a population of more than 20 million inhabitants living on an area of about 619 square kilometres (239 sq mi).