Originally this was a series of reservoirs built by the West India Dock Company and completed in 1828.

The West India Dock Company built the reservoirs to provide clean impounded water to keep the water level in the docks high and so prevent an influx of water and mud when the entrance locks were opened at high tides. Each of the reservoirs was 650 feet by 110 feet. They were fed from the river on every high tide. The bottom of each reservoir inclined upwards. A steam engine pumped settled water into the upper reservoir, which sluiced directly into the Blackwall Basin and entrance lock.

The steam engine proved inadequate and so, in 1831, James Watt replaced the twin pumps with a single ’Great Pump’.

The upper reservoir was filled in 1838–9 because its site was required for the London and Blackwall Railway. The reservoirs were converted into a timber pond in 1844.

Poplar Dock was then converted into a railway dock, in the days before any of London’s enclosed dock systems were connected to the railway network. It was built by the East & West India Docks and Birmingham Junction Railway Company and connected to the company’s goods yard at Chalk Farm. It opened as such in 1851.

The dock, used for coal and export goods traffic, was extended to the west in 1875–7 to provide depots for other railway companies.

It was alone among the docks to remain outside the control of the Port of London Authority in 1909, and remained in the ownership of British Rail until closure in 1981.

Much of the dock survives today as a mooring connected to Blackwall Basin and is now known as Poplar Dock Marina, being opened as that by Queen Elizabeth II in 1999.