Southwest of the Colovian Highlands, the Brena River and the mountains of the Colovian Highlands form the northwest border of Cyrodiil. On the other side of the river is the province of Hammerfell. A shipwreck is located at the mouth of the river.
- If the Hero has a high enough acrobatics, it is possible to jump up and walk around on a very minuscule part of Hammerfell in The Elder Scrolls IV: Oblivion (even with the borders on). To do this, one must swim across from the shipwreck at the mouth of the river to the Hammerfell coast and repeatedly jump until they reach a small, flat area in Hammerfell. It is not a very big area, however.