In more senses than one, ethnicity is about borders. Land, understood as the ancestral property of the ethnic group or as its divinely sanctioned share that has to be won back, is a decisive factor of ethnic self-consciousness. Therefore the border, ideally understood as the specific place where the territory of one ethnic group ends and that of another ethnic group begins, and in reality most often an ambiguous zone of shifting allegiances, is a privileged point from which to observe and analyze the emergence, development, and reaffirmation of ethnicity. Marking and patrolling the border is a vital symbolic function for any ethnic group, while the inherent instability of the border is an endless creator of ethnic renegotiation. However, the importance of borders and boundaries for the definition of ethnic communities goes beyond their territorial dimension. Ever since the pathbreaking studies of Fredrik Barth it has been clear that ethnic boundaries should not be understood simply as imaginary lines that delimit a territory. On a deeper level, they are complex systems of norms and expectations that make it possible to identify the people who belong to the ethnic community and to exclude those who do not.

In Barth's view, the boundaries themselves are what really defines the group, more than any characteristics that may be associated with its members.