A maritime boundary is a conceptual division of the Earth's water surface areas using physiographic or geopolitical criteria. As such, it usually bounds areas of exclusive national rights over mineral and biological resources, encompassing maritime features, limits and zones. Generally, a maritime boundary is delineated at a particular distance from a jurisdiction's coastline. Although in some countries the term maritime boundary represents borders of a maritime nation that are recognized by the United Nations Convention on the Law of the Sea, maritime borders usually serve to identify the edge of international waters.
Maritime boundaries exist in the context of territorial waters, contiguous zones, and exclusive economic zones; however, the terminology does not encompass lake or river boundaries, which are considered within the context of land boundaries.