Alma 22:29

And thus the Nephites were nearly surrounded by the Lamanites; nevertheless the Nephites had taken possession of all the northern parts of the land bordering on the wilderness, at the head of the river Sidon, from the east to the west, round about on the wilderness side; on the north, even until they came to the land which they called Bountiful.

From section: Mormon’s Description of Nephite and Lamanite Geography

From page: Mormon Abridges the Nephite Records