TLDR
Tennessee and Missouri tie for the most bordering states, with 8 each. Kentucky has 7, and Colorado reaches 7 only if you count Arizona, which it touches at a single point.
The ranked list
Here are the top tiers among the 48 contiguous states. Counts include neighbors across a river, but not neighbors across a lake or the ocean.
| Bordering states | State | Neighbors |
|---|---|---|
| 8 | Tennessee | Kentucky, Virginia, North Carolina, Georgia, Alabama, Mississippi, Arkansas, Missouri |
| 8 | Missouri | Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas, Nebraska |
| 7 | Kentucky | Illinois, Indiana, Ohio, West Virginia, Virginia, Tennessee, Missouri |
| 7 | Colorado | Wyoming, Nebraska, Kansas, Oklahoma, New Mexico, Utah, plus Arizona at a corner point |
| 6 | Arkansas | Missouri, Tennessee, Mississippi, Louisiana, Texas, Oklahoma |
| 6 | Idaho | Washington, Oregon, Nevada, Utah, Wyoming, Montana |
| 6 | Iowa | Minnesota, Wisconsin, Illinois, Missouri, Nebraska, South Dakota |
| 6 | Nebraska | South Dakota, Iowa, Missouri, Kansas, Colorado, Wyoming |
| 6 | Oklahoma | Kansas, Missouri, Arkansas, Texas, New Mexico, Colorado |
| 6 | Pennsylvania | New York, New Jersey, Delaware, Maryland, West Virginia, Ohio |
| 6 | Wyoming | Montana, South Dakota, Nebraska, Colorado, Utah, Idaho |
| 6 | Utah | Idaho, Wyoming, Colorado, Arizona, Nevada, plus New Mexico at a corner point |
That’s the whole podium. Everything below 6 is a long tail of states with 5 or fewer neighbors.
Why Tennessee and Missouri border so many states
Geography did most of the work. Both states sit in the middle of the eastern half of the country, so there are simply more directions in which a neighbor can appear.
The other factor is the Mississippi River. It runs along the entire western edge of Tennessee and the eastern edge of Missouri, and rivers make ragged, wandering borders. Missouri’s boundary with Illinois, Kentucky and Tennessee all follows the river, and Tennessee’s western edge gives it Arkansas and Missouri across the water.
Tennessee is also long and thin, about 440 miles from east to west. That stretch lets it touch the Mid-South states at one end and the Appalachian states at the other. Missouri is blockier, but its jagged southern “bootheel” pokes down between Arkansas and Kentucky/Tennessee, adding contact points.
How borders get counted
Most of the confusion in this topic comes from three edge cases.
Corner points. Colorado, Utah, Arizona and New Mexico meet at Four Corners, the only spot in the US where four states share a point. Colorado and New Mexico share a real border, as do Utah and Arizona. The diagonal pairs, Colorado-Arizona and Utah-New Mexico, touch at one point only. Most sources, including those that give Colorado 7, count them. Strict “shared line” counters drop Colorado to 6 and Utah to 5.
Water borders. Rivers count. Lakes and sea boundaries usually don’t, which is why Michigan, Illinois and Wisconsin don’t get extra neighbors from Lake Michigan in the table above. Island countries follow the same logic at national scale: Tonga has no land neighbors at all.
The Kentucky Bend. Kentucky has a small exclave of roughly 17 square miles that hangs off the Mississippi, cut off from the rest of the state by a river loop. It’s attached by land to Tennessee and Missouri only, which is why Kentucky’s count of 7 includes both. The Cumberland Gap, where Kentucky, Tennessee and Virginia meet, is the more visitable tri-state spot.
If you want the underlying data, the US Census Bureau publishes official state area and boundary files.
FAQ
Which state borders the fewest states? Maine, with one: New Hampshire. Alaska and Hawaii have none.
Do any other states have just two neighbors? Yes. Florida (Alabama and Georgia), Rhode Island (Connecticut and Massachusetts) and Washington (Oregon and Idaho) each have two.
Are any state borders disputed? A few. Georgia has pushed for decades to move its northern line with Tennessee a mile or so north, based on an 1818 survey error, so it could reach the Tennessee River. It hasn’t worked.
Does Washington, DC count? No, it isn’t a state. If you count it as a neighbor, Virginia and Maryland each gain one.
Is the answer the same for all 50 states? Yes. Alaska and Hawaii have no state neighbors, so they don’t change the top of the list.
