On October 17, 1870, the British colonial government enacted the Calcutta Port Act (Act V of 1870), bringing the Port of Calcutta under the management of a statutory body — the Calcutta Port Commissioners. Prior to this, attempts to manage the port via a “river trust” or municipal control had proven inadequate. 

At the time of this reorganisation, the port operated with just four jetties and one wharf, capable of berthing 52 vessels (~48,000 tons). Within a year (1871–72), these figures expanded to six jetties serving 143 vessels with net tonnage ~222,000. 

The new Board comprised representatives from Bengal’s Chamber of Commerce, Indian commercial interests, railways, and other stakeholders.  This administrative shift enabled more systematic oversight, infrastructure development, and trade facilitation, cementing the port’s role as a linchpin in British India’s eastern commerce.