During this period, the total area of the docks was increased from 82 to 192 acres (0.78 km2), and the length of the quays was 15 miles (24 km) by 1857.

Manchester Dock and the adjacent Chester Basin were dangerously subsiding because of excavation works for the Queensway Tunnel which ran underneath the site.

[4] The area later became a car park, sealing the remains under a protective layer of tarmac.

In 2006/7, the dock was excavated as part of a major construction project for the new Museum of Liverpool and the Leeds and Liverpool Canal link to the Canning and Albert Docks.

[5] These excavations also exposed the neighbouring Chester Basin, and have provided important archaeological information as the entrance lock is one of the oldest in the whole Liverpool Docks complex.