Jerusalem was a Lamanite city and land in the land of Nephi, built by the Lamanites together with the Amalekites and the people of Amulon. Aaron, one of the sons of Mosiah, took his journey toward it; the settlers had named it after the land of their fathers’ nativity, and it lay adjoining the borders of Mormon (Alma 21:1-2).
Aaron came to the city and first preached to the Amalekites in their synagogues, which were built after the order of the Nehors. An Amalekite contended with him, and when Aaron began to expound the coming of Christ and the resurrection, the people grew angry, mocked him, and would not hear; he departed to a village called Ani-Anti (Alma 21:4-11). Of the Amalekites only one was converted, and none of the Amulonites; they hardened their own hearts and those of the Lamanites among whom they dwelt (Alma 23:14).
When part of the Lamanites converted and took the name of Anti-Nephi-Lehi, those in the land of Jerusalem who were not converted were stirred up by the Amalekites and Amulonites to anger against their brethren and took up arms against the people of Anti-Nephi-Lehi (Alma 24:1-2). At the time of the crucifixion of Christ the city was destroyed: the Lord caused waters to come up in its place, to cover the wickedness of its inhabitants (3 Nephi 9:7).
The record places Jerusalem adjoining the borders of Mormon (Alma 21:1), the place where Alma baptized at the waters of Mormon in the borders of the land of Nephi (Mosiah 18:4, 16; Alma 5:3).