The Maratha Ditch was a three-mile-long[1] deep entrenchment constructed by the English East India Company around Fort William in Calcutta.

[2][3][4][5] The ditch marked the outer limits of Calcutta city in the nineteenth century.

In 1742, the president of the East India Company in Bengal petitioned the nawab Alivardi Khan to create an entrenchment intended to circle the landward sides of Calcutta.

[6] After that, it became more or less useless as a defensive work, since the deteriorated ditch could only make the movement of troops and artillery significantly difficult.

[2] Today, a road in North Kolkata by the name of Maratha Ditch Lane marks where the entrenchment once stood.