Which U.S. state is bordered by only ONE other state?

Maine: America's Most Isolated State

Tucked into the far northeastern corner of the country, Maine holds a genuinely unique place in American geography. Of all 50 states, it is the only one that shares a land border with just a single other U.S. state — New Hampshire, to its southwest. Every other state in the contiguous U.S. touches at least two neighbors. Maine stands alone.

Why So Isolated?

Geography explains it perfectly. Maine is essentially a peninsula jutting into the North Atlantic, hemmed in on three sides by water and foreign soil. To the north and northwest, it shares a long international boundary with the Canadian provinces of Quebec and New Brunswick — roughly 611 miles of it. To the east and southeast, the Atlantic Ocean forms its coastline, one of the most rugged and iconic in the entire country. That leaves only one direction — southwest — where Maine connects to another American state, and that's where New Hampshire steps in.

The Maine-New Hampshire border is relatively short, running only about 58 miles, largely defined by the Salmon Falls River and the Piscataqua River before reaching the sea near Portsmouth. It's a border you can cross in minutes, yet it's Maine's only land link to the rest of the United States.

A State Set Apart

This geographic quirk has real consequences for how Maine operates. Drive from Maine to any state other than New Hampshire, and you have to pass through New Hampshire first. There's no shortcut. Historically, this isolation shaped Maine's culture, economy, and even its path to statehood. Maine was originally part of Massachusetts, separated from it by a large swath of New Hampshire land. It didn't become its own state until 1820, entering the Union as part of the Missouri Compromise as a free state to balance Missouri's admission as a slave state.

Bigger Than You Think

Maine is also surprisingly large for a northeastern state. At around 35,380 square miles, it's bigger than all five other New England states combined. Most of that land is dense forest — nearly 90% of the state is tree-covered — and much of it is sparsely populated. Moose outnumber people in several counties. That vast, wild interior reinforces the sense that Maine exists in a world slightly apart from the rest of America.

The Easternmost Point in the U.S.

Add one more superlative to the list: Maine is home to the easternmost point in the entire United States. West Quoddy Head, a lighthouse-topped headland near Lubec, is the first place in the country to see the sunrise each morning. It's a fitting distinction for a state that, geographically speaking, has always been out on its own.

Maine's single-state border isn't just a trivia curiosity — it's a window into the state's whole identity: independent, remote, and unlike anywhere else in America.