Ditch to the northwest of Oxford. There are a whole series of discontinuous earthworks with gaps between them. The whole complex covers an area of around 80 km2. There are two circuits of earthworks whose relationship is unknown. Excavation has shown the earthworks were built in the late Iron Age and went out of use by the Roman period. There is a suggestion that the earthworks are part of an oppida but if this is the case then it would be the largest one in Britain. The north Oxfordshire Grim's Ditch is visible as a shallow ditch and a raised area south of North Leigh (accessible from the New Yatt footpath), in the woods west of Stonesfield (near the Blenheim Park boundary wall), running north near Grim's Dyke Farm at Glympton Assets, in the woods to the north of Glympton Assets and south-east of Ditchley Park. A third Grim's Ditch is found on the Berkshire Downs and lies north of the county boundary between Oxfordshire and West Berkshire, running for near the Ridgeway, above the Oxfordshire villages of Ardington, Hendred and Chilton. This is thought to be of late Bronze Age date. West Yorkshire The West Yorkshire Grim’s Ditch was recognised in the 1970s through the work of Dr Margaret Faull on the place names of West Yorkshire. It had escaped the attention of Yorkshire antiquarians because of the poor state of preservation. The Grim’s Ditch runs north to south between Leeds and Castleford with the ditch is the eastern side. Late medieval documents only refer to the northern section as Grim’s Ditch. The Grim’s Ditch needed substantial effort to build as the ditch was cut into the shale bedrock in parts. Radiocarbon dates from material excavated during archaeological work on the A1 (M) upgrading showed the Grim's Ditch was probably Iron Age in date with possible Roman reuse. Locations British National Grid references See also Anglo-Saxon paganism Devil's Dyke, Cambridgeshire, an earthen barrier in eastern Cambridgeshire Devil's Dyke, Hertfordshire, a prehistoric defensive ditch in Hertfordshire Toponymy of England Notes References Henig, M, Booth, P. and Allen, T. (2000) Roman Oxfordshire, Sutton Publ, 244 p, Sauer, E. (1999) "Middleton Stoney/Upper Heyford, Aves Ditch, earthwork and tribal boundary of the Iron Age", South Midland Archaeol., 29, 65–69 Archaeological sites in England Archaeological sites in Berkshire Archaeological sites in Hampshire Archaeological sites in Oxfordshire Ancient dikes Linear earthworks