According to Jerry Ainsworth, the name Cori-antum-r may might have some reference not only to the land Antum, where Ammaron hid up all the engravings concerning "this people" in the hill Shim (see Mormon 1:3), but to the location where Coriantumr was found by the people of Zarahemla (see Omni 1:21). The historian Ixtlilxochitl appears to pinpoint the location of a meeting with surviving Jaredites when he says: "On the banks of the Atoyac river, which is the one that passes between Puebla and Cholula . . . they found some of the giants that had escaped the calamity and extermination of the second age." The Atoyac River begins east of the continental divide in the state of Puebla, Mexico. [Jerry L. Ainsworth, The Lives and Travels of Mormon and Moroni, pp. 82-83]
“Antum”
According to Jerry Ainsworth, the name Antum apparently has something to do with water. Nephi relates how "we beheld the sea, which we called Irreantum, which, being interpreted, is many waters" (1 Nephi 17:5). Hugh Nibley notes that the Egyptian term an-t refers to water, while the word Iaru, a non-Semitic name, anciently referred to the Red Sea (Collected Works of Hugh Nibley, 7:171-72).
Because Irre-antum identifies a place where waters end up, it's possible that antum identifies a place connected with waters. If Ammaron had referred to the area of the Hill Shim as the land of Antum, that would have implied it was named after a person, as were other Nephite lands. Rather, he referred to it in such a way as to possibly imply that the name was descriptive; it might have identified what the place was like.
According to Ainsworth, Ammaron's description of the land best fits the valleys of Puebla and Tlaxcala in Mexico. These adjoining valleys are surrounded by four volcanoes covered with snow. The two western-most volcanoes sit on the continental divide. From that point, waters flow to both the western and eastern seaboards. The area is indeed descriptive of where waters originate, or a "land Antum" (see illustration). The chief ancient city of these valleys is Cholula, which nestles at the foot of the snow-covered volcanoes. Its Olmec name is Atlxoloayan, which means "Where the Waters Begin to Flow" or, literally, "The Place of the Fleeing of the Waters."
A prominent hill, called Malinche, sits in the middle of the Valley of Puebla (see illustration). Its numerous caves are considered taboo by the local inhabitants. They will not allow anyone to enter them on threat of death. People who have attempted to enter have lost their lives; some have had narrow escapes. Perhaps in one or more of these caves Ammaron hid the plates containing the Nephite records. Perhaps this is the hill Shim. [Jerry L. Ainsworth, The Lives and Travels of Mormon and Moroni, pp. 145-146]
Mormon 1:3 The land Antum ([Illustration]): Map 24. The Land Antum. [Jerry L. Ainsworth, The Lives and Travels of Mormon and Moroni, p. 147]
Mormon 1:3 The land Antum ([Illustration]): 73. The Hill Malinche in the state of Tlaxcala, Mexico; possible site of the Hill Shim. [Jerry L. Ainsworth, The Lives and Travels of Mormon and Moroni, p. 148]