This report is part of the study ‘Analysis of Cross-border obstacles between EU Member States and Enlargement Countries’. It is looking to increase the effectiveness and efficiency of Interreg IPA programmes and supporting border regions in overcoming challenges due to national borders. The study is a comprehensive review of existing external cross-border obstacles and identifies obstacles that can impact the five Policy Objectives and two Interreg Specific Objectives of the 2021-2027 programming period. The study also offers ideas on how Interreg IPA programmes can address these obstacles in the future. The geographic focus of the study is on the borders between EU Member States and candidate and potential candidate countries. The study builds on an extensive literature analysis, a survey of stakeholders and case studies. This report is the result of a joint analysis of these sources and their triangulation. Annex I details the methodological approach of the study. The core data has been integrated in an inventory of obstacles for cross-border cooperation. This report presents the main findings of the study.