The White Horse Stone is a name given to two separate sarsen megaliths on the slopes of Blue Bell Hill, near the village of Aylesford in the south-eastern English county of Kent. The Lower White Horse Stone was destroyed prior to 1834, at which time the surviving Upper White Horse Stone took on its name and folkloric associations. Various archaeologists have suggested—although not proven—that the stones were each part of chambered long barrows constructed in the fourth millennium BCE, during Britain's Early Neolithic period. If the White Horse Stones were originally components of chambered long barrows, then they would have been erected by pastoralist communities shortly after the introduction of agriculture to Britain from continental Europe. Long-barrow building was an architectural tradition widespread across Neolithic Europe although comprised various localised regional variants; one of these was in the vicinity of the River Medway, examples of which are now known as the Medway Megaliths. The White Horse Stones lie on the eastern side of the river, along with the chambered long barrows of Little Kit's Coty House, Kit's Coty House, the (now destroyed) Smythe's Megalith, and the Coffin Stone, which may be a part of a fourth. Three other examples, the Coldrum Long Barrow, Addington Long Barrow, and Chestnuts Long Barrow, remain on the western side of the river. Excavation has revealed the existence of an Early Neolithic longhouse near to the stone.

By the 19th century, antiquarians were speculating that the Lower White Horse Stone may have taken its name from the White Horse of Kent, which they in turn believed was the flag of the legendary fifth-century Anglo-Saxon warriors Hengest and Horsa. Subsequent historical research has not accepted this interpretation. After the stone was destroyed, the stories associated with it were transposed to a nearby sarsen boulder, which became known as the Upper White Horse Stone. Since at least the 1980s, the latter has been viewed as a sacred site by various Folkish Heathen groups, including the Odinic Rite, because of its folkloric associations with Hengest and Horsa and the Anglo-Saxon Migration. As well as performing rituals there, they have opposed vandalism of the stone and campaigned to stop development in the vicinity. The Early Neolithic was a revolutionary period of British history. Between 4500 and 3800 BCE, it saw a widespread change in lifestyle as the communities living in the British Isles adopted agriculture as their primary form of subsistence, abandoning the hunter-gatherer lifestyle that had characterised the preceding Mesolithic period.[1] This came about through contact with continental European societies, although it is unclear to what extent this can be attributed to an influx of migrants or to indigenous Mesolithic Britons adopting agricultural technologies from the continent.[2] The region of modern Kent would have been key for the arrival of continental settlers and visitors, because of its position on the estuary of the River Thames and its proximity to the continent.[3]

Britain was then largely forested;[4] widespread forest clearance did not occur in Kent until the Late Bronze Age (c.1000 to 700 BCE).[5] Environmental data from the vicinity of the White Horse Stone supports the idea that the area was still largely forested in the Early Neolithic, covered by a woodland of oak, ash, hazel/alder and Amygdaloideae.[6] Throughout most of Britain, there is little evidence of cereal or permanent dwellings from this period, leading archaeologists to believe that the island's Early Neolithic economy was largely pastoral, relying on herding cattle, with people living a nomadic or semi-nomadic life.