The Swedish district courts have undergone a substantial restructuring process in which the main reform has been to merge. As a result, the number of district courts has declined from 95 in 2000 to only 48 in 2009. All main arguments that support merging concern enhancements of efficiency. However, it has not yet been explicitly examined whether the mergers have the potential to increase efficiency ex ante. Thus, the expectation concerning higher efficiency was built on a subjective view. This paper investigates whether the mergers can be rationalized from a production economic point of view. Data envelopment analysis (DEA) is used to compute a production frontier where the conducted mergers are incorporated to identify the potential ex ante gains. Furthermore, the overall potential is decomposed into learning, scale, and harmony to investigate the source of the potential gain, e.g., an effect of adjusting to best practice or a pure merging effect such as scale. The results show diverse potentials, i.e., a number of mergers did not have the potential to gain in efficiency while others could gain substantially. A conclusion based on the analysis is that the potential production economic effects should be investigated before merger decisions are made in the future. This is also likely to be true beyond the Swedish district courts.