This article engages with political region building by examining the diverging conceptions of the Baltic Sea region since the 1970s. Itmaps the fuzzy geography arising from the enmeshment of territory with a multitude of frameworks for regional action. After 1989, the region became the object of interregional and neighborhood policies established by the European Union, with shifting territorial delimitations according to various internal and geopolitical needs of the day. Drawing on functional, relational, and administrative perspectives, it is shown how spatial definitions surrounding the Baltic Sea region have varied over the past fifty years, revealing those transnational connections that have been valued as worthwhile political investments.