Voluntary mergers of local jurisdictions in Europe gained in importance in the last two decades. A debated but rarely analyzed issue in this field is the impact of different local characteristics on the probability to merge. The paper contributes to this debate by assessing the importance of local determinants in two stages of a merger process. The quantitative study of a large-scale territorial reform in the Swiss canton of Fribourg shows that factors linked to the functional dimension of local government, such as economic hardship, explain the start of a merger process but not the decision taken at the ballots. Here, factors associated with the political dimension of local government, such as political power considerations, offer a better explanation. These findings might be explained by the variation of different political actors’ strength along the two stages of a merger process.