Salsette Island is an island in Konkan division of the state of Maharashtra, on India's west coast. Administratively known as Greater Mumbai, the city district of Mumbai, Mumbai Suburban district, Mira Bhayander, and a portion of Thane 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 .
Salsette is bounded on the north by Vasai Creek, on the northeast by the Ulhas River, on the east by Thane Creek and Mumbai Harbour, and on the south and west by the Arabian Sea. The original seven islands of Mumbai, which were merged by land reclamation during the 19th and early 20th centuries to form the city of Mumbai, are now practically a southward protruding peninsula of the much larger Salsette Island.
The island of Trombay that was to the southeast of Salsette is today part of Salsette as much of the intervening swamps have been reclaimed. It contains Borivali National Park, also known as Sanjay Gandhi National Park. The city of Thane is at the northeastern corner, on Thane Creek, while the western suburbs of Mumbai which stretches from Bhayandar in the northwest corner to Bandra which lies just before the Mumbai City district lies on its western side while the eastern suburbs of Mumbai that stretches from Thane to Kurla lies on the eastern half of the island. Both suburbs are separated by the Borivali National Park till the neighbourhood of Powai in Andheri. Politically, the Mumbai City district covers the peninsula south of Mahim and Sion while most of the original island constitutes the Mumbai Suburban district. The northern portion lies within Thane district, which extends across Thane creeks onto the mainland.
History of Mumbai
The word Sasashti (also shortened to Sashti) is Marathi for "sixty-six", referring to the original "sixty-six villages" on the island.