Middle Ground, an island in the Mumbai Harbour has a fortified naval base known as the Middle Ground Coastal Battery. The Middle Ground Coastal Battery is an islet off the coast of Mumbai (Bombay) in the Indian state of Maharashtra. The isle is situated a few hundred metres away from the Gateway of India and lies in the Thane Creek. The islet originated from a piece of hard basalt rock, emerging from the creek bed and having an area of a few hundred square metres.

The Middle Ground Coastal Battery was once part of a reef, like the nearby Oyster Rock. After the setting up of the British East India Company in Bombay, the Middle Ground Island was fortified in 1682 to restrain the sea piracy in the area. Later a marine police force comprising of Bhandaris were appointed there to keep an eye on the pirates who used to board ships. The Bhandaris were chosen for their loyalty, honesty and local knowledge. With their yellow turbans and blue trousers, the police were a formidable sight. After piracy moved to the South China Sea, about two hundred years ago, the police were disbanded and the Royal Navy gained control of the Middle Ground.