Delaware.
The Sun Belt spans the southern USA from Florida to California. California is the furthest west Sun Belt state.
what state makes up most of arkansas' southern border
The US state of South Dakota is the southern border of North Dakota.
Arkansas
Virginia
At the beginning of the US Civil War, the "southern" border States were Kentucky and Missouri. In this answer, Maryland is excluded in that although it was a pro=southern slave State, it cannot be considered a border State.
The Ohio River
It is Missouri.
Kansas is the US state on the southern border of Nebraska. The capital city of Kansas is Topeka.
what state makes up most of Arkansas' southern border
Mississippi's southern border is further south than Georgia's southern border. Georgia's southern border is 30.356 degrees north. Mississippi's southern border is 30.12 degrees north.