Our mental maps of the world, including our perceptions of where regions begin and end, can have profound consequences on strategic behavior. For decades there has been a sharp division between what we understand to be the regions of South Asia and Southeast Asia. The line between them effectively cuts the Bay of Bengal in two. These perceptions have inhibited a proper analysis of the strategic dynamics of the area. This article argues that the Bay of Bengal increasingly matters as a strategic space. Like, the South China Sea, security issues in the Bay of Bengal and its littoral states need to be understood and addressed in a coherent manner.