joint flooding,perhaps?
-Location of major rivers or large lakes-Boundaries between countries and states
Those are international borders, which represent the limits of a country's territory. They are often defined by natural features like rivers or mountains, or through agreements between neighboring countries.
Mesopotamia was defined as the land between the Tigris and Euphrates Rivers.
rivers
Mountains, rivers, oceans, and deserts were natural features that served as boundaries between culture areas.
The Ohio and Mississippi rivers outlined the boundaries of the Western and Southern boundaries of the Northwest Territory.
Basicly political boundaries are the boundaries that governments claim to have rule over and natural boundaries are ones set by following the paths of natural landmarks, like rivers, valleys, or mountain ranges.
The Tigris and the Euphrates served as boundaries of Mesopotamia.
County lines typically follow natural boundaries like rivers, mountains, or roads, while international boundaries are usually defined by treaties between countries. In some cases, they may be marked by physical barriers like fences, walls, or checkpoints. The specific delineation of county and country lines is determined by historical agreements, land surveys, and legal documents.
Georges Kaeckenbeeck has written: 'Divergences between British and other views on international law' -- subject(s): International law 'De la guerre a la paix' -- subject(s): Treaties, International law 'International Rivers' -- subject(s): International rivers
Jamaica is a self contained island - it has no land boundaries.