Wikipedia
According to The Book of Mormon, the land of Amulon was located in the greater land of Nephi.
We first learn of the land of Amulon in the book when a group of the former priests of king Noah, led by a man named Amulon, escape with the 24 daughters of the Lamanites and began to settle and till the land. For a time they lived undiscovered until the armies of the Lamanites that had followed the people of Limhi got lost in the wilderness and stumbled upon the people of Amulon . Amulon, by authority of the Lamanite king, is made teacher over the people in the land Amulon and other areas .
The land Amulon is not mentioned again until some 35 to 60 years later in . The Amalekites (probably Amlicites) and Amulonites, as well as some of the Lamanites living in the land of Amulon and other areas were not converted and were angry at those who were converted.
According to the Book of Mormon, Amulon was a Nephite that lived in the 2nd century BC. He was one of the wicked priests of the ill-fated King Noah. Upon King Noah's death and the invasion of the Lamanites into the land of Nephi, Amulon and a group of priests (later dubbed Amulonites) fled into the wilderness where they kidnapped 24 Lamanite women to be their new wives. The Amulonites were later found by the Lamanite army in a place which they had named Amulon (after their leader). After persuading the Lamanites to spare their lives, the people joined the Lamanites in going returning to the land of Nephi, only to stumble upon the group settled at Helam, led by Alma the Elder (who was also once a priest of King Noah). Amulon was then placed as a puppet ruler by the Lamanites over the people at Helam.