Fort William is a fort in Hastings, Calcutta. It was built during the early years of the Bengal Presidency of British India. It sits on the eastern banks of the Hooghly River, the major distributary of the River Ganges. One of Kolkata's most enduring Raj-era edifices, it extends over an area of 70.9 hectares.
The fort was named after King William III. In front of the Fort is the Maidan, the largest park in the country. An internal guard room became the Black Hole of Calcutta. Today it is the Headquarters of Eastern Command of the Indian Army.