The Northern border - jokingly called the "longest undefended border in the world."
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
The weather does a pretty good job of keeping folks on the highways in winter in these parts, the distance between where you are and anywhere does well the rest of the time.
Even jackrabbits pack a lunch and carry a canteen...