Scholars increasingly use Swiss cantons to examine the effect of democratic processes and institutions on political, economic and social outcomes. However, the availability of political indicators at the cantonal level is limited, in particular for longer periods of time. We introduce a novel data set on the ideological and partisan composition of cantonal governments, covering the period 1848-2017 for most cantons. In this research note, we describe our data collection efforts and present some descriptives on the political development of cantonal governments in order to illustrate the data's potential. In particular, we look at the political strength of different parties and factions, the number of parties in government, government volatility and the nationalization of the party system. Our data thus provide new opportunities to examine political, economic and social outcomes as well as the formation of party systems in the Swiss cantons.