SummaryTHE VIABILITY OP LOWER SIZE‐ORDER SETTLEMENTS IN RURAL AREAS THE CASE OF NORTH‐EAST ENGLANDUsing North‐East England as a study area, it is suggested that certain critical thresholds may be observed with respect to the viability of rural settlements. The first, and most important, relates to the grade 2 centres of sub‐regional market towns which, facing competition from larger industrialised centres, need to be assured of their economic future. A second threshold seems to occur for settlements with a minimum adult population of 450, for these contain a more advanced social provision for a semi‐mobile society which can avoid the need for frequent long‐distance travel to a grade 2 or grade 1 centre. A third seems to occur at about 120–140 adults since this appears to be the lowest notable growth grade and provides the minimum social provision for a non‐mobile society. Lasdy, and simply in terms of population, a setdement of 50–60 adults represents the threshold between moderate and severe losses of population. It is stressed that these conclusions have been reached from research carried out in a region which has suffered from economic decline and structural change since the 1930s. But they might be borne in mind by rural planners in the future restructuring of the patterns of setdement in the countryside.