Based on a survey of 2010 citizens in four large metropolitan areas in Switzerland, the analysis presented in this article shows that spatial mobility of citizens across municipal borders leads to an upscaling of their territorial identities at the level of the city-region. On the one hand, this results in a favorable attitude towards encompassing institutions at the city-regional scale. On the other hand, given the high degree of institutional fragmentation prevailing in Swiss city-regions, strong city-regional orientations lead to a delegitimization of the local political system. Without adequate reforms of the territorial institutional framework, the ongoing growth and functional integration of city-regional spaces will lead to political alienation and increasingly challenge the democratic legitimacy of the local state in Switzerland. Beyond the Swiss case, the article shows that the long-running debate on metropolitan governance should focus, more thoroughly than in the past, on issues of citizenship and democratic legitimacy.