What natural barriers separate Scotland and England?

The natural barrier that separates Scotland and England is the Cheviot Hills, a range of hills that runs along the border between the two countries. The Cheviot Hills are not particularly high, with the highest point being The Cheviot at 815 metres (2,674 ft), but they are steep and rugged, making them difficult to cross. This has helped to keep the two countries distinct from each other, both culturally and politically.