In this chapter, the authors zoom in on the organizational forms, policy portfolios and venue selection of regions at the EU level. They provide a literature review and address how multilevel governance shapes the relations between subnational authorities and the central government. The authors discuss the scope and diversity of EU-level territorial mobilization, and clarify why some sub-state jurisdictions are more likely to be active at the supranational level. They take a closer look at the role of liaison offices, and address their activities in Brussels in more detail. An analysis of the policy portfolio of 127 regional representations demonstrated that they mostly have a quite generalist orientation. On average, these actors indicated to monitor developments in about 11 policy domains, which implies that their policy interests in Brussels are usually quite broad and encompassing. The authors focus on the extent to which regional representations focus on multiple venues, or rather prioritize interaction with certain institutions in their lobbying activities.