In this paper, we explore to what extent the Norwegian Local Government Reform of the 2010s affected local political trust. Following Hansen (2013), we regard a large-scale municipal amalgamation reform as a quasi-experiment. Such a reform makes it possible to compare trends in merged and non-merged municipalities, and thereby separate the effects of changes in size from other trends. However, this approach creates a new problem: how can the effect of the reform process be separated from the effect of size as such? Hansen argues that if changes in size itself matters, the junior partners in a merger – who experience a larger change – will differ from both senior partners and unmerged municipalities. We will explore this potential difference, but also compare trust in local and national politicians, since the size of the national political unit is unchanged. We use data from the Norwegian Local Election Studies of 2011 and 2019 (before and at the time of the merger), and compare the development of trust in local and national politicians in 1) unmerged municipalities, 2) ‘senior partners’ in merged municipalities, and 3) ‘junior partners’ in merged municipalities.