Natural
The Colorado River forms the west boundary of Arizona with California and Nevada.
The Colorado river
Colorado River
Most likely it is the Gila (hee-ya) river
it is china and mongolia russia and spain japan and france australia to california now that is some examples of a political and a natural boundary
The Alps mountain range forms a natural boundary between France and Italy.
Australia's natural boundry is the ocean.
Lake Victoria acts as a boundary between Tanzania, Uganda, and Kenya. Another natural boundary between these countries is the Kagera River.
none it is entirely artificial
The Ural and Caucasus Mountains form part of the natural boundary between Europe and Asia.
The Ural and Caucasus Mountains form part of the natural boundary between Europe and Asia.
diaphragm