The Stones of Stenness, a Neolithic henge and stone circle located on the Orkney Islands in Scotland, are estimated to have been constructed around **3100 BCE**. This date is based on archaeological evidence and radiocarbon dating from the site and similar monuments in the region, such as the nearby Ring of Brodgar. The Stones of Stenness are part of the Heart of Neolithic Orkney, a UNESCO World Heritage site, and are considered one of the oldest known henge monuments in the British Isles.Excava