This paper describes the distribution of reaves (Bronze Age land boundaries) on North and East Dartmoor (cf. Fleming 1978a for South Dartmoor). It is suggested that they form a pattern which reflects the territorial arrangements of several communities distributed around the edge of Dartmoor. Each of these territories tended to be about 3–4 km in breadth and to include a single block of enclosed land laid out on one axis, sometimes covering over 1000 ha. The scale of territories here is more independent of the incidence of major geographical features than is the case on South Dartmoor. There is normally a simple division between enclosed land and upland pasture, without the intermediate settled valley zones which are important on the South Moor. Classic parallel reave systems occur, but so do simpler ‘block systems’, and this variability can best be conceptualized as a continuum, within a broad tradition of laying out enclosed land on a major axis and in rectangular parcels. It is suggested, mainly on the basis of the interdependence of the pattern's components, that most boundaries on Dartmoor were laid out in response to a single decision taken around 1300 bc (1700/1600 BC), although some cross-ridge reaves may be earlier in date. Some details of the layout reflect different levels of social organisation — what are here termed the neighbourhood group, the community, and the regional level of organisation. The paper also discusses the settlement history of different regions of Dartmoor, suggesting that a third major upland common, the East Moor, should be considered equivalent to the North Moor and the South Moor in terms of the development of land use. The East Moor was eventually encroached upon by the Rippon Tor parallel reave system, probably the largest prehistoric field system known in Britain.