Spatial patterns and territorial-administrative structures in Eastern Europe are a mix of historical-territorial path-dependencies influenced by the current path-creating policies. Since the early 2000s, the European Union (EU) policies, practices and challenges have concerned also Eastern Europe. This article discusses spatial patterns and territorial-administrative structures in theory, illustrates their practices and presents scenarios for their future in the EU contexts. The Europeanization of spatial policy and planning and the territorial-administrative structure harmonization are the key current trends. The transposition and implementation of the EU spatial policy mechanisms and practices in Eastern Europe are influenced by contextual path-dependent legacies and the uncertain long-term future of the EU. Conditionality as governmentality and relational regions open new perspectives to territorial dynamics in the EU and Eastern Europe.