Alma 50:34

And it came to pass that they did not head them, until they had come to the borders of the land Desolation; and there they did head them, by the narrow pass which led by the sea into the land northward; yea, by the sea, on the west, and on the east.

The army did not catch them until they got to the land Desolation. They caught them at the narrow pass that led to the land in the north. The pass went by the sea on the west and on the east.

They didn’t catch them until they reached the borders of the land Desolation. There, at the narrow pass between the seas—the pass that led north along the coast—they blocked their path.