Sundered Hills

The Sundered Hills is a region located somewhere within The Reach and is most known for being the birth place of the Red Eagle. It can be assumed that the Sundered Hills was one of the 10 kingdoms of the Reach during the Red Eagle's time period.

Location
It is not specifically mentioned where the Sundered Hills are in the Reach but it is most likely the large elevated area between Rorikstead and Karthwasten because this is the area that the Red Eagle's quest takes place at as well as the location of two old towers known as the Sundered Towers.

How large the region is isn't known though the name may refer to the entire mountain range on the east side of the Karth River.

Refrences
1. The Legion of Red Eagle (Book)