One of the most fundamental but overlooked questions in shaping a national territorial-development strategy is how to manage spatial development in regions that have not been selected for new growth. The Irish National Spatial Strategy (NSS) is ostensibly a policy exercise in spatial selectivity where clear choices have been made as to where to target future population growth. The failure of policy to implement the NSS to date can be largely attributed to the difficult political process in practice of identifying 'winners' and 'losers'. In order to achieve the public consensus required for effective implementation, a revised strategy will need to pay greater attention to the residual regions. This will require a greater societal acceptance that population growth cannot occur everywhere, and that population decline and stagnation may become the normal pathway for some regions. This paper explores planning governance models of how to manage decline, drawing on the emerging international research agenda of 'shrinkage planning' and 'de growth', and how this might be applied in the Irish context. In so doing, the paper provides policymakers with the genesis of a new conceptual toolbox and opens up new research questions as to how to proactively design and accommodate depopulation.