Wikipedia
Ammaron
Ammaron should not be confused with Amaron, Ammoron, or Amoron, three other Book of Mormon figures with similar names.
According to the Book of Mormon, Ammaron (Ammoron a frequent scribal variant in the Printer's Manuscript) was a Nephite record-keeper and perhaps a prophet. He was also one of the authors who wrote on the Plates of Nephi, which Mormon abridged.
Ammaron took custody of the Nephite records after the death of his brother, Amos, in AD 306 and three verses contain Mormon's abridgment of his writings. In 321, he hid all the Nephites' sacred writings in the Hill Shim in the Land of Antum. He later instructed the ten-year-old future prophet Mormon to wait until he was twenty-four and then take the Plates of Nephi from the hill (leaving the other writings hidden) and continue the record.