Geographic: Since the army of Shiz is fleeing, and the army of Coriantumr stops at Ramah, we may understand that when the army of Shiz flees southward, it takes them from north of Ramah to south of the hill. The pursuing army would not easily have been able to move past a fleeing army, and therefore they are following.
Moroni very clearly connects the hill Ramah of the Jaredites to “that same hill where my father Mormon did hide up the records unto the Lord.” That hill was known to the Nephites as Cumorah.