Flagstones is a late Neolithic interrupted ditch enclosure (similar to a causewayed enclosure) in the English county of Dorset. The enclosure is formed by a ring of pits dug into the chalk bedrock, with 'causeways' between the pits. Half of the enclosure was discovered beneath the site of the demolished Flagstones House in advance of the construction of the Dorchester by-pass road. The part of the enclosure in the grounds of Flagstones House was partially excavated archaeologically, by Wessex Archaeology, and then the grounds were totally removed to make a deep cutting for the bypass at this point. The other half still exists under the grounds of Max Gate, Thomas Hardy's house.
The 100 m diameter enclosure itself contained a variety of human remains in its pits including those of a two or three year old child beneath a sandstone slab and a newborn baby crushed in the terminal of a pit. A young man had been buried in a later Early Bronze Age tumulus in the centre of the site beneath a sarsen megalith. Carbon dating of the remains put the building of the enclosure at around 3486–2886 BC with the central burial dating to around a thousand years later. Neolithic carvings were found carved into the sides of three of the pits.