Mumbai consists of two distinct regions: Mumbai City district and Mumbai Suburban district, which form two separate revenue districts of Maharashtra.The city district region is also commonly referred to as the Island City or South Mumbai.The total area of Mumbai is 603.4 km2 (233 sq mi)Of this, the island city spans 67.79 km2 (26 sq mi), while the suburban district spans 370 km2 (143 sq mi), together accounting for 437.71 km2 (169 sq mi) under the administration of Municipal Corporation of Greater Mumbai (MCGM).

Mumbai lies at the mouth of the Ulhas River on the western coast of India, in the coastal region known as the Konkan. It sits on Salsette Island (Sashti Island), which it partially shares with the Thane district.Mumbai is bounded by the Arabian Sea to the west. Many parts of the city lie just above sea level, with elevations ranging from 10 m (33 ft) to 15 m (49 ft); the city has an average elevation of 14 m (46 ft). Northern Mumbai (Salsette) is hilly,and the highest point in the city is 450 m (1,476 ft) at Salsette in the Powai–Kanheri ranges.