The Mississippi River is the boundary between Tennessee and Arkansas.
The border between Mississippi on the west and Arkansas on the east is the Mississippi River. It also forms the border between Arkansas and Tennessee.
which river runs across the state of Arkansas
Arkansas is to the east of the Mississippi River. Arkansas's western border is not only bordering, but entirely drawn out by the Mississippi River.
There are either 3 or 4 states - Missouri is entirely east of the Arkansas and west of the Mississippi, because the Arkansas does not enter the state. - Parts of Kansas, Oklahoma, and Arkansas (where it joins the Mississippi) can be considered "between " the two.
The Mississippi River runs between Tennessee and Arkansas. The Mississippi River forms the western boundary of Tennessee and separates Tennessee from both Arkansas and Missouri.
Tennessee is separated from Arkansas by the Mississippi River.
The Mississippi River forms most of Arkansas's eastern border.Mississippi River
The major tributary of the Mississippi River that flows in the southeasterly direction to join the Mississippi River near St. Louis is the Missouri River. The Missouri River and the Mississippi River join at the border between Missouri and Illinois.
The Arkansas River
The Mississippi River forms most of Arkansas's eastern border. Tennessee and Mississippi border Arkansas to the east across the Mississippi River.
I am pretty sure your answer is the Arkansas river.