The Largest Anglo-Saxon Dyke in Britain
Stretching in a near-straight line across the chalk landscape of south Cambridgeshire, Devil's Dyke is the largest Anglo-Saxon earthwork in Britain. It runs for more than seven miles from the Fen edge at Reach, past Newmarket Heath, and on towards the clay ridges at Woodditton. In places the bank rises to around ten metres from the bottom of the ditch, making it one of the most impressive surviving monuments of early medieval England.
A Defensive Barrier on Newmarket's Doorstep
The dyke's relationship with Newmarket is immediate and visible. It runs along the edge of the July Course at Newmarket Racecourse, where training gallops now trace the same corridor of open downland that the earthwork has defined for more than a millennium. At the Rowley Mile, the dyke has been levelled to allow the racecourse to cross it; horses can start a race in Cambridgeshire and finish in Suffolk, passing directly over the line of the ancient ditch and bank.
The earthwork was strategically placed to block a narrow land corridor between the marshy Fens to the north and the wooded hills to the south. This natural bottleneck made circumvention difficult, and the dyke formed an effective defensive barrier for the lands to the east. It is also believed to have controlled movement along ancient trackways, including the Icknield Way.
Dating the Earthwork
Excavations carried out in 1923 and 1924 found Roman artefacts beneath the dyke, confirming that it was built after the Roman period. Although long assumed to be Anglo-Saxon, radiocarbon dating of the similar Fleam Dyke in the 1990s produced an earliest construction phase between AD 330 and 510, suggesting that some of these great earthworks may have roots in the late Roman or very early post-Roman era. The Anglo-Saxon Chronicle records that in 905 Edward the Elder laid waste to land "between the Dyke and the Ouse as far northward as the Fens," a passage often interpreted as a reference to Devil's Dyke. In the late tenth century, Abbo of Fleury described East Anglia as "fortified in the front with a bank or rampier like unto a huge wall, and with a trench or ditch below in the ground."
Protection and Public Access
Devil's Dyke is a scheduled monument, a Site of Special Scientific Interest, and a Special Area of Conservation. Although much of the land it crosses is privately owned, a public footpath runs along its length, giving walkers a continuous route from Reach towards Woodditton. The path offers one of the most direct ways to experience the scale of the monument and its integration with the modern landscape of fields, gallops, and the eastern fringe of Newmarket.