this is the question I'm asking
From what I know, it is not a river that forms much of the border. It is the Bitterroot mountain range.
The Nez Perce are the Native American people who once inhabited the lower Snake River. The Snake River rises in northwest Wyoming and flows through southern Idaho up through southeast Washington to the Columbia River.
the Mississippi river
The Snake River originates in Wyoming near Yellowstone National Park. It travels through Idaho, Oregon, and Washington as well as a small bit of Utah and Nevada before joining the Colombia River in Washington and emptying into the Pacific Ocean.
The Mad River rises in the Cascade Mountains and flows southeast to join the mouth; the Entiat River.
The major river of Southeast Asia flowing through Laos Thailand, Vietnam and Cambodia is the Mekong.
The river Ganga.
Washington DC is on the Potomac River. On the far side is Virginia (Arlington, and the Pentagon). To the southeast is the Anacostia River.
Potomac River
Most of the Snake River is in southern Idaho. It starts in Wyoming, crosses Idaho, runs north along the border with Oregon, and ends in southeast Washington where it joins the Columbia River.
The Ebro river flows southeast from beginning to end.
Colorado river