The location of the City Ammonihah provides support for our premise that Nephi’s Land of Nephi (i.e. where the City of Nephi was), is west of the Land of Zarahemla, not south. We know that the Hermounts wilderness was west and north of the City of Zarahemla:
37 Yea, they were met on every hand, and slain and driven, until they were scattered on the west and on the north, until they had reached the wilderness which was called Hermounts; and it was that part of the wilderness which was infested by wild and ravenous beasts.
38 And it came to pass that many died in the wilderness of their wounds, and were devoured by those beasts and also the vultures of the air; and their bones have been found, and have been heaped up on the earth. (Alma 2)
We assume that the Hermounts wilderness was a small, unique area that was avoided, nevertheless we recognize that it did exist in or near the area going to the Land of Ammonihah. (See it identified on the Watershed Map)
3 Alma departed from [City Zarahemla] thence and took his journey over into the land of Melek, on the west of the river Sidon, on the west by the borders of the wilderness. [Hermounts?]
6 So that when he had finished his work at Melek he departed thence, and traveled three days’ journey on the north of the land of Melek; and he came to a city which was called Ammonihah. (Alma 8)]
Thus, Ammonihah was west and three days journey north of the City of Zarahemla.
It is untenable to believe that the City and Land of Nephi were south of the Land of Zarahemla and that the enemy would travel north to the Land of Zarahemla and bypass cities along the southern border, and the City of Zarahemla, and travel an additional three days (or more for troops) just to arrive at a remote location to invade.
Strategically it makes no sense to take a city on the furthest side of your enemies strong hold (City of Zarahemla), however, if you’re already on the west of the City of Zarahemla and the northern quadrant of your land is adjacent to the city you want to invade, it makes sense.
1 And now it came to pass that, as soon as Amalickiah had obtained the kingdom [City & Land of Nephi] he began to inspire the hearts of the Lamanites against the people of Nephi;
6 And it came to pass that they took their camp, and moved forth toward the land of Zarahemla in the wilderness. (Alma 48)
1 And now it came to pass in the eleventh month of the nineteenth year, on the tenth day of the month, the armies of the Lamanites were seen approaching towards the land of Ammonihah. (Alma 49)
25 And it came to pass, that when the Lamanites saw that their chief captains were all slain they fled into the wilderness. And it came to pass that they returned to the land of Nephi, to inform their king, Amalickiah, who was a Nephite by birth, concerning their great loss. (Alma 49)