The Missouri River
The river flowing between Washington and Oregon is the Columbia River.
The Mississippi river was the border.
The Red River
GA gained land stretching all the way down to the st. Mary's river ( where our southern border is today)
The Snake River forms part of Oregon's eastern border
Columbia River, Oregon.
The Columbia River.
Columbia river
Columbia river
The Columbia River.
The Dalles is located in the state of Oregon on the Columbia River, Oregon's northern border with Washington state.
The Columbia River forms a major part of the border between the states of Oregon and Washington.
This is the river Danube.
The Columbia River forms most of the border between Oregon and Washington before flowing into the Pacific Ocean.The river that forms part of the border between two northwestern states and flows into the pacific ocean is the Columbia river.
West Virginia, Ohio, Illinois, and Indiana form the northern border of Kentucky, along the Ohio River.
The Columbia River lies between the States of Washington and Oregon, and forms the border between the two.