This chapter describes the process by which a cross-border metropolitan region develops, using the example of the Greater Region. Between 2008 and 2010 the idea of a cross-border, polycentric metropolitan region in the Greater Region was investigated and further developed within the ESPON project 'Metroborder'. In recent years, driven by policy declarations, strategic approaches for implementing this metropolitan region have been developed. A Spatial Development Strategy of the Greater Region with a focus on the metropolitan dimensions of the sub-regions provides the foundation for this. The issue of governance in relation to the crossborder interactional area (in the narrower conception of this area) is also discussed. ; begutachtet (peer reviewed) ; Veröffentlichungsversion ; peer reviewed ; Published Version