This chapter discusses the important distinction between artificial boundaries and natural boundaries. Artificial boundaries, such as national and state borders, are defined as boundaries that are products of human decisions and stipulations, an expression of collective intentionality that translates into political, social, and legal agreements whereby it is determined where a certain territory begins and where it ends. Such artificial boundaries may be drawn with great accuracy or left vague or underspecified; it all depends on the importance we attribute to the relevant demarcations and on the role they play in our lives. Natural boundaries, such as geographic boundaries, are by contrast characterized by their independence from human organizing activity; they are boundaries that exist on their own. Their existence cannot be ignored like in the case of artificial boundaries, the existence or non-existence of which is the subject of controversy.