The Snake River forms part of Oregon's eastern border
From what I know, it is not a river that forms much of the border. It is the Bitterroot mountain range.
Columbia river
The Columbia River forms a major part of the border between the states of Oregon and Washington.
the river that forms the border between India and Kentucky is the Mississippi River.
The Colorado River forms the border between Arizona and California.The Colorado River.
The Colorado River forms the border between Arizona and California
The Mississippi River forms Iowa's eastern border, the Missouri forms the western border with Nebraska while the Big Sioux river forms the border with South Dakota.
Rio Grande forms some of the border.
The Colorado River forms the border between Arizona and California.The Colorado River.
The Mississippi River forms the wavy western border of Illinois. And the Ohio Wabash River is the southern border of Illinois.
The Colorado River forms the border between California and Arizona.