The Duddo Stones were known as the Four Stones until 1903, when the fifth stone was re-erected to improve the skyline.
There were originally seven stones, the empty sockets of two stones being found on the western side during excavation in the 1890s.

The stones are formed of a soft sandstone. They have become deeply fissured by natural weathering since erection in the Early Bronze Age, around 4,000 years ago.