A divide
Springfield, Illinois and Frankford, Kentucky are the capitals of two states that border the Mississippi River.
1729
A watershed is the area separating two different drainage basins/river systems.
UN Resolution 181.
Columbia River
The population of a given state can decide, by referendum, if they wish to divide their state into two states.
Washington and Oregon
Georgia and Alabama
For the most part the Savannah river borders the states of South Carolina and Georgia.
The Red River actually flows through four states. These states include Texas, Oklahoma, Arkansas, and Louisiana. This river is1,360 miles long.
Columbia River