Natural
The Colorado River forms the west boundary of Arizona with California and Nevada.
Colorado River
The Colorado river
The geographic feature that forms the border between Arizona and California is the Colorado River. This river flows southwest from the Rocky Mountains and serves as a natural boundary between the two states for much of its length. Additionally, the border is marked by various reservoirs and lakes created by damming the river, such as Lake Mead and Lake Havasu.
Most likely it is the Gila (hee-ya) river
The river that forms the border between Arizona and California is the Colorado River. This river flows southward from the Rocky Mountains and creates a natural boundary between the two states as it travels through the southwestern United States. It is also known for its significance in providing water resources and its stunning canyons, including the Grand Canyon.
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.
The Mississippi River serves as the natural boundary between Mississippi and Louisiana.
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