The caves are artificial, having been carved out of the soft sandstone rock by prospective dwellers, and have grown to become a complex network under the city. The oldest date back to 1250.[25] The city has more manmade caves than anywhere else in the country and this whole cave network has Scheduled Ancient Monument protection equal to that of Stonehenge, making Nottingham Caves a site of vast importance to the heritage of the United Kingdom. Part of the network can be viewed by the public at the City of Caves attraction which is accessed from the upper mall of the Broadmarsh Shopping Centre.

Before the industrial revolution, the cave network was substantially expanded and became home to a large proportion of the poorer populace, particularly those involved in the tanning industry. The majority of the caves were thought to have been used for storage by the 18th century and were still inhabited until around 1924 when the last family (the Shore family) moved out of the caves in Ilkeston road; they came into use again as air raid shelters during World War II. A section of the cave network under the Broadmarsh Shopping Centre is now open as a tourist attraction, and some parts are still used as pub cellars.

Another section of the caves, under the castle, is still in regular use as the indoor rifle range of the Nottingham Rifle Club. In addition, Ye Olde Trip to Jerusalem Inn, a pub that claims to be the oldest in Britain, is partly built into the cave system below the castle and still retains access from the beer cellars to the castle through the cave inside castle rock. Although the pub’s building only dates from the 16th or 17th century, the caves themselves may date to the 11th century and could have been the site of the brewhouse for the castle.