There are 7 citations to the east wilderness, where there only 2 referring to the south wilderness. There is no “west wilderness” cited just wilderness in the west.The same goes for a north wilderness just “the wilderness which was north…” type of verse. There is the narrow strip of wilderness mentioned once but only as a geographic reference point. Most of the times the east wilderness is mentioned as a strategic military region.
Here is what we know or can derive about the east wilderness. It was east and north of the land of Zarahemla. It was east of the river Sidon, the south wilderness, the land of Jershon and east of the land of Antionum where the Zoramites lived. It was probably on the northeast side of the land of Nephi and close to the sea east.
It was an area occupied with Lamanites and as such it exposed the land Bountiful to a Lamanite invasion. As such it became increasingly important that the Nephites occupy this wilderness and fortify it.
Moroni’s first strategic move was to occupy the east wilderness, from the sea east to the west sea. This was about 70 BC. “And it came to pass that Moroni caused that his armies should go forth into the east wilderness; yea, and they went forth and drove all the Lamanites who were in the east wilderness into their own lands, which were south of the land of Zarahemla. And it came to pass that when Moroni had driven all the Lamanites out of the east wilderness, which was north of the lands of their own possessions, he caused that the inhabitants who were in the land of Zarahemla and in the land round about should go forth into the east wilderness, even to the borders by the seashore, and possess the land. (Alma 50:7,9)
Moroni’s second strategic military move was to fortify the east wilderness against potential attacks from the Lamanites. “And he also placed armies on the south, in the borders of their possessions, and caused them to erect fortifications that they might secure their armies and their people from the hands of their enemies. And thus he cut off all the strongholds of the Lamanites in the east wilderness that they might secure their armies and their people from the hands of their enemies. (Alma 50:10)
The last thing we read is that Moroni builds cities in that eastern zone. “And it came to pass that the Nephites began the foundation of a city, and they called the name of the city Moroni; and it was by the east sea; and it was on the south by the line of the possessions of the Lamanites. And they also began a foundation for a city between the city of Moroni and the city of Aaron, joining the borders of Aaron and Moroni; and they called the name of the city, or the land, Nephihah. Alma (50:13-14)
From all this relocation and fortification came what we call today as the peace dividend. “But behold there never was a happier time among the people of Nephi, since the days of Nephi, than in the days of Moroni, yea, even at this time, in the twenty and first year of the reign of the judges.” (Alma 50:23) That’s a bold statement for Mormon to make given there has been 500 years from the days of Nephi. Of course if anyone could make that judgment, Mormon could.