The Rio Grande, St. Lawrence, Niagara, Rainy, Pigeon, St. Clair, St. John, St. Croix, Colorado, and St. Mary's rivers.
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
The Ohio and Mississippi rivers outlined the boundaries of the Western and Southern boundaries of the Northwest Territory.
Mountains, rivers, oceans, and deserts were natural features that served as boundaries between culture areas.
Which river form the boundaries of the Great Lakes states
Rivers, mountain ranges, oceans, etc. Those are considered "natural boundaries".
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.
Jamaica is a self contained island - it has no land boundaries.