Boundaries can be some of the simplest and most provocative lines on a map. These lines ask us to accept political borders as being as natural to the landscape as a mountain range. They are supposed to definitively mark long-lasting—if not permanent—political divisions. Most of all, they claim to constitute a national identity for those within them. At the same time, as maps like the one of nineteenth-century Louisiana in this section highlight, these boundary lines make concessions when unruly natural, geographical features interrupt them; they frequently change in response to global events; and they cannot tell the whole story of the historical, cultural, or political loyalties of the people within them. In their search for permanence, these boundary lines often end up exposing their own limitations.