This paper proposes that a “borderlands” is a functional category of analysis focusing on spatial overlap of political units and cultures, while a “frontier” is the perceived boundary of human activity or normative cultural behavior. By adopting this paradigm, a comparison is made of seascapes and wastelands as frontiers in the context of Ottoman dominium over the Black Sea and the adjacent deşt-i kıpçak in the 16th century. Further comparison is made of the administration, conceptualization, and utilization of space and resources in both cases. Ultimately, the north Black Sea coast is examined as a “figurative littoral” separating two spaces, sea and steppe, which posed numerous shared challenges to Ottoman rule.