High Quality Content by WIKIPEDIA articles! The Mersey Docks and Harbour Company (MDHC), formerly the Mersey Docks and Harbour Board (MDHB), owns and administers the dock facilities of the Port of Liverpool, on the River Mersey, England. These include the operation of the enclosed northern dock system that runs from Princes Dock to Seaforth Dock, in the city of Liverpool and the dock facilities built around the Great Float of the Wirral Peninsula, located on the west side of the river.