The Williamson Tunnels are a labyrinth of tunnels in the Edge Hill area of Liverpool, England, which were built under the direction of the eccentric businessman Joseph Williamson between 1810 and 1840.
They remained derelict, filled with rubble and refuse, until archaeological investigations were carried out in 1995. Since then excavations have been carried out and part of the labyrinth of tunnels has been opened to the public as a heritage centre.
In 1805 Joseph Williamson acquired an area of land in Mason Street, Edge Hill, Liverpool, which was then a largely undeveloped outcrop of sandstone with a scattering of scars from small-scale quarrying.
He started to build houses on the site. These houses were eccentric in design "of the strangest description" without any rational plans. The ground behind the houses dropped sharply and in order to provide large gardens, which was the fashion at the time, Williamson built arches over some of the quarrying, and arched terraces over which the gardens could be extended.
When these were complete he continued to employ his workmen, sometimes to carry out apparently pointless tasks, such as moving rubble from one place to another, then back again.
His major project was to build a labyrinth of brick-arched tunnels in various directions and over various lengths within the sandstone. This tunnel-building continued until Williamson's death in 1840.
In August 1867 the Liverpool Porcupine described the tunnels as being "a great nuisance" because drains ran straight into them, in one place creating a cess pool full of offensive water 15 feet (5 m) deep, and they were being used for dumping refuse,including down chutes built into the buildings above for the purpose.