Many international borders seem permanent and carefully planned. In reality, some exist because of mapping errors, misunderstood geography, or simple surveying mistakes made centuries ago.
1. The Northwest Angle
The Northwest Angle is a small piece of Minnesota that can only be reached by land through Canada.
Its unusual shape exists because mapmakers negotiating the U.S.–British border in 1783 mistakenly believed the Mississippi River extended much farther north than it actually does. The error remained in later treaties, leaving this isolated pocket of the United States.
2. Baarle-Hertog and Baarle-Nassau
The towns of Baarle-Hertog (Belgium) and Baarle-Nassau (Netherlands) contain one of the world’s most confusing borders.
Medieval land agreements left dozens of tiny Belgian enclaves inside the Netherlands—and even Dutch enclaves inside some Belgian ones. Today, streets, homes, and even businesses can sit in two different countries.
3. Bir Tawil
Between Egypt and Sudan lies Bir Tawil, one of the few places on Earth claimed by neither country.
Conflicting colonial-era boundary descriptions created a situation where both nations claim the nearby Hala’ib Triangle but reject ownership of Bir Tawil because accepting it would weaken their larger territorial claim.
4. Point Roberts
Point Roberts, Washington, is attached to Canada but separated from the rest of the United States.
When the U.S.–Canada border was established along the 49th parallel, surveyors followed the line exactly, unintentionally leaving this small American community cut off from the mainland.
5. The Gambia
The narrow shape of The Gambia reflects colonial negotiations between Britain and France during the 1800s.
Britain controlled only the territory along the Gambia River, creating one of the world’s most unusual national borders almost entirely surrounded by Senegal.
6. Mount Everest’s Border
The border between Nepal and China follows the Himalayan ridgeline, but early surveys struggled to determine the exact position of the world’s highest peak.
Improved mapping eventually clarified the boundary, though modern survey techniques continue refining measurements of Everest itself.