The article explores how the notion of European integration at the local level can be conceptualized and measured. Based on a process-oriented inclusive understanding of integration and using relational datasets that maps both domestic and cross-border communication ties among political representatives in four Euroregions along the borders of Hungary–Slovakia and Sweden–Norway, we begin by applying and theoretically dissecting network-analytical metrics based on frequency of ties. Despite finding that such measures capture analytically relevant properties of political cross-border networks, we argue that they are less than ideal for capturing the notion of political integration. Instead, with inspiration from the blockmodeling tradition in network analysis, we propose two novel metrics—cross-border connectivity and integrational overfitting. These metrics not only enrich our understanding of political integration in cross-border settings but also can serve as useful mapping tools for policy-makers. A software client enabling the analysis of these measures supplements this article.