The Mississippi River does not physically touch all five U.S. regions (Northeast, Midwest, South, West, Pacific). It flows entirely within the Midwest and South.
It does not enter the Northeast (no), the West (Rocky Mountains, Great Basin—no), or the Pacific (coastal states—no). Its *watershed* (drainage basin) covers 41% of the lower 48, reaching into the West (Montana, Wyoming via Missouri River tributary) and even a tiny bit of the Northeast (southwestern NY via Allegheny), but the *river itself* stays central.
The Mississippi is the spine of *Middle America*—not a transcontinental connector.