According to Alma 2:9, the Amlicites first "gathered" to supposedly one area in order to elect a king, then in verse 2:15 they "came" to the hill Amnihu. The question arises, from what territories did they "gather," and where did they gather to? It is my opinion that the Amlicites came towards the local land of Zarahemla from downstream (from the direction of Ammonihah). However, I believe that there might have been some strong ties to what eventually was called the land of Manti upstream from Zarahemla (Alma 16:6). These ties might explain the ability of a Lamanite army to easily negotiate the general borders of the Nephite land. [Alan C. Miner, Personal Notes] [See the commentary for Alma 2:15; 16:11; 24:28]
“The Hill Amnihu”
Although the "hill Amnihu," first mentioned in Alma 2:15, was "east of Sidon" we don't know at this point how far east of the river Sidon it was, or how far away from the local land of Zarahemla it was, or in what exact direction (northeast, east, southeast) from the local land of Zarahemla it was located. According to Alma 2:19, apparently from the start of the battle on the hill Amnihu, the Nephites pursued the Amlicites all day before coming to the valley of Gideon and "pitching their tents" (Alma 2:20). Since the beginning of the battle was "upon the hill" (Alma 2:17), that "hill" was apparently part of the same topography that produced the "valley" of Gideon within one day's march. It is hard to tell at this time whether the Nephites had to march any big distance from the local land of Zarahemla before they reached the hill Amnihu to start the "day" mentioned in verse 2:19. [Alan C. Miner, Personal Notes] [For a comparable battle that might have been close to this location, see Alma 3:20-23]