The paper explores the relationship between constitutional representations of the nation and institutional design following the partitions of Ireland and the Indian subcontinent. The constitution-making processes and outcomes in Ireland 1937, India 1950 and Pakistan 1956, together with the Northern Ireland Act 1998, reveal the constitutional centrality of claims to nationhood that extend beyond state borders. The contested lands of NI and Kashmir have shaped the constitutional settlements of independent Ireland, India and Pakistan and the UK’s devolution framework. We investigate how postcolonial constitutions have dealt with the idea of a truncated nationhood and the legacy of armed conflict over contested lands in both foundational and institutional terms. We focus on the interplay of an extra-territorial definition of the nation with questions of territorial autonomy and fundamental rights to explain the impact of partition on constitutional settlements and governmental authority.