Chapter 5 attempts to identify the areas in West Africa that have the greatest potential for cross-border co-operation. It is based upon research that maps seven environmental, socio-economic and political indicators, highlighting the existence of wide spatial disparities between West African regions. The research indicates that the zones with the greatest potential for cross-border co-operation are concentrated in southern Senegambia, along the borders of Burkina Faso, in the Accra-Lagos conurbation, between Niger and Nigeria, and in the north of Cameroon, as these regions present greater cross-border accessibility and border market density than others. In particular, they share natural, agricultural or pastoral resources, do not face significant linguistic divides, and poverty gaps are neither too wide nor too narrow, promoting synergies and movement between countries. From an institutional perspective, it is easier to roll out cross-border programmes in those areas where the relevant borders are well delimited.