Alma 22:33

And it came to pass that the Nephites had inhabited the land Bountiful, even from the East unto the West sea, and thus the Nephites in their wisdom, with their guards and their armies, had hemmed in the Lamanites on the south, that thereby they should have no more possession on the north, that they might not overrun the land northward;

The Nephites had lived in the land Bountiful from the east to the west sea. In their wisdom, with their guards and their armies, they had boxed in the Lamanites on the south. That way the Lamanites would have no more land on the north. They could not take over the land to the north.

The Nephites had settled in Bountiful from the eastern sea to the western sea. With their guards and armies, they’d wisely boxed the Lamanites in on the south so they couldn’t possess any northern territory and couldn’t overrun the land to the north.