The Nine States That Border the Mississippi River

America's Great River as State Border

The Mississippi River forms all or part of the boundary for ten states—but only nine have the river as a border (the tenth, Minnesota, contains only the headwaters). Listed north to south:

1. Minnesota – Source at Lake Itasca; river flows entirely within state initially.
2. Wisconsin – Western border (vs. MN, IA); 300+ km.
3. Iowa – Eastern border (vs. WI, IL); 500+ km.
4. Illinois – Western border (vs. IA, MO); 900+ km.
5. Missouri – Eastern border (vs. IL, KY, TN); 600+ km.
6. Kentucky – Western border (vs. MO); ~100 km (only Mississippi border).
7. Tennessee – Western border (vs. MO, AR); ~200 km.
8. Arkansas – Eastern border (vs. TN, MS); 500+ km.
9. Mississippi – Western border (vs. AR, LA); 500+ km.
10. Louisiana – River splits (delta); borders MS, but also flows through state to Gulf.

Border vs. Interior

• Border states (9): WI, IA, IL, MO, KY, TN, AR, MS, LA.
• Interior state (1): MN (headwaters only).
• Louisiana is both border (vs. MS) and interior (delta distributaries).

Historical Significance

• Northwest Ordinance (1787) used river as territorial divider.
• Missouri Compromise (1820) – slavery boundary at 36°30′ (river-adjacent).
• Civil War – control of river = control of continent (Vicksburg, New Orleans).