The Book of Mormon never states or even infers that the various groups of people mentioned in its pages were the only peoples living in the Americas during the time period of approximately 2500 BC to 300 BC during the Jaredite period; or from 590 BC to 421 AD during the Nephite/Lamanite period. On the contrary, there are numerous suggestions and indications that there were other groups of people with which the main Lehite colony, or its sub-parts, came in contact. Following are the scriptural references of many passages that suggest or infer the existence of other groups of indigenous peoples.
2 Nephi 1:5-11 – Other peoples would be led to the Americas. These could have preceded the Book of Mormon people.
2 Nephi 5:6-9 – All those who would go with Nephi: inferring there were others besides his own family and those mentioned by name.
2 Nephi 5:15-16 – Within barely 30 years after leaving Jerusalem, the Nephites had built a large temple. In that short period of time there probably weren’t more than 100 Nephites, many of whom would have been children or teenagers, so the inference is that there must have been many other able-bodied men, enough to construct the temple in addition to their own homes.
2 Nephi 5:34 – After only 30 years in the New World (essentially only 40 years since leaving Jerusalem) the Nephites had already had wars with the Lamanites (in only 2 generations); and there would have been only approximately 150 people on each side, hardly enough to be considered having a war unless thousands of indigenous peoples were also involved.
2 Nephi 10:20-22 – Jacob says he thinks the Nephites “are upon an isle of the sea.” (At least it appears to be an island to the Nephites, being surrounded by water.) There are multiple “isles of the sea . . . and they are inhabited also by our brethren.” (Again, not necessarily actual islands.) The Lord has led these other Israelites away from Jerusalem (or Israel/Palestine), possibly to other parts of the New World.
2 Nephi 29:7, 12-14 –God remembers the seed of Abraham and will give His word to them. (wherever they may be.)
Jacob 1:14 – People friendly to Nephi are called Nephites; those who want to destroy the people of Nephi are called Lamanites, not necessarily blood descendants on either side.
Jacob 3:13 – The Nephites had become numerous. This is a general statement but there is a suggestion that more than direct descendants of the Lehite colony were involved.
Jacob 7:1-6 – Sherem had never met Jacob even though the direct descendants of Nephi, Sam, Zoram, Jacob, and Joseph were very few in number, ~ less than 80-100.
Jarom 1:6 – Lamanites were more numerous than Nephites. Why? Initially, Laman, Lemuel, and 2 sons of Ishmael became Lamanites – 4 groups. Nephi, Sam, Zoram, Jacob, and Joseph became Nephites – 4-5 groups. Possibly the Lamanite families were joined by more indigenous peoples than were the Nephites.
Mosiah 24:5-7 – Groups of Lamanites were friendly with each other, yet occasionally fought among themselves except with their own tribes.
Mosiah 25:3 – Lamanites were more numerous than Nephites and Zarahemlaites (Mulekites) combined. They may have conquered other indigenous groups south of the narrow strip of wilderness.
Mosiah 25:12 – Whenever outsiders joined with Nephites they were called Nephites.
Mosiah 29:44 – Reign of the judges was established among all the people who were called Nephites. The inference being that there were other peoples besides descendants of the Lehite colony.
Alma 3:11 – Whoever didn’t believe in the Lamanite traditions were called Nephites, inferring there were others than direct descendants of the Lehite colony.
Alma 3:17 – Nephi’s "seed" consists of whoever follows him (regardless of lineage).
Alma 7:1 – Alma speaks to the people of Gideon “in my language.” This possibly infers that the people of Gideon, although members of the general Nephite nation, were of a different lineage than Alma, being a pure Nephite; and that they had learned the Nephite language so that he could communicate with them, but that he didn’t know their specific language or dialect.
Alma 7:6 - The Gideonites were a humble people, not prideful nor set upon riches and vain things. They may have been a completely different people than those in Zarahemla, who were prideful and concerned about worldly things, yet both groups part of the Nephite nation.
Alma 17:26 – "Lamanitish" servants – why this designation if they were not true Lamanites? Alma 19:16 states that Abish (secret Church convert) was one of the Lamanitish servant women. What is a Lamanitish woman compared to a true Lamanite woman?
Alma 21:2-5; 22:7; 24:1, 28; 27:12; 43:6, 17 – The Amalekites were a hard-hearted, wicked group of otherwise unidentified people living among the Lamanites in the land of Nephi. Some LDS scholars propose that the name Amalekites had been misspelled by Oliver Cowdery when writing the manuscript and should actually be the Amlicites, followers of a Nephite dissenter named Amlici, who, along with many of his followers, may have been other than pure Nephites. (see Alma 2:1-38; 3:1-18.) The Amalekites were definitely of a different lineage than the Lamanites. (see Alma 24:29.)
Alma 30:6 – Korihor came into the land of Zarahemla. If the “land of Zarahemla” means the entire land, that is the nation of the Nephites, then it means that he was a non-Nephite coming from another group of people who were not Nephites. Some LDS researchers have shown that Korihor is a Jaredite name and that he may have been a descendant of some Jaredites who had not perished the great civil war that ended the Jaredites as a people. If, however, the “land of Zarahemla” means the local county-like area immediately around the city of Zarahemla, then Korihor could have been a Nephite (still possibly with Jaredite ancestry or perhaps just bearing a Jaredite name) from another land within the greater land of Zarahemla.
Alma 31:35 – Many of the Zoramites were brethren of Alma and his missionary group. This infers that others of the Zoramites, possibly the majority, may have been of a different lineage than the original Lehite colony. The Zoramites, in general, were dissenters from the Nephites (see Alma 31:8).
Alma 43:17 – Amalekites are mentioned as dissenters from the Nephites, yet nowhere previously in the record is it mentioned when they dissented, unless they are the Amlicites who did defect and join the Lamanites. (See Alma 21:2-5, etc., above.)
Alma 50:32 – Why was Moroni concerned that the people in the Land Bountiful would join with the rebellious people from the land of Morianton unless they were of a different lineage and prone to be rebellious against the established Nephite authority?
Alma 51:8, 21 – The Kingmen were of high birth. Where did they come from? Were they descendants from the Zarahemlaites, thus from Mulek who was of high birth; or were they a completely separate group of people assimilated earlier into the Nephites from a culture that had nobility and high births, and were now becoming disaffected?
Helaman 1:15 – Coriantumr(2), a defector to the Lamanites, was a direct descendant of the Mulekites. It appears that some of this lineage may not have been happy that their ancestors joined with the Nephites and that all their subsequent kings were only from pure descendants of Nephi.
3 Nephi 3:9-10 – The leaders of the Gadianton band may have been part of the dissenters, like the Amlicites, who felt they should have had more privileges being of noble birth or other separate ancestry.
3 Nephi 3:14, 24 - “... all them who were numbered among the Nephites....” (possibly inferring that there were other peoples besides the Nephites and converted Lamanites who were friendly to the Nephite leadership).
3 Nephi 7:2-4, 14 – During the anarchy and the formation of numerous tribal associations before Christ’s coming to America – it would be interesting to know if the tribes that developed were based on prior ethnicity.
4 Nephi 1:10, 23 – The Nephites “multiplied exceedingly fast” - could this have been augmented by many converts from other nearby peoples as well as those who were already Nephites?
Mormon 1:7 – Nephites were extremely numerous. See question immediately above. Mormon 4:17 - “... greatness of number....” - raises again the question of natural increase or amalgamation of other indigenous or other non-Nephite peoples.
Ether 7:11 - “...for the people had become exceeding numerous.” The time period appears to be between 75 and 150 years after the arrival of the Jaredites in the new world. Jared and Mahonri’s descendants, along with the other 22 people or couples’ descendants, probably would not total more than 1000 people. It is difficult to say what “exceeding numerous” means, of course, but if they had joined with thousands of locals (Olmecs) then there could easily have been a numerous people under the title of Jaredites.
Ether 7:23 – Prophets were sent by the Lord among the Jaredites. Were these prophets literal descendants of the original Jaredite colony who came across the ocean, or were they raised up from indigenous peoples?
Ether 10:1-4 – Apparently a famine destroyed most of the Jaredites, but in a short time during Shez’s(1) reign “the people began again to spread over all the face of the land.” Again, this is very general, but it could be accounted for by combining with indigenous people.
Ether 10:21 – Within 200 – 300 years after Shez’s reign, “the whole face of the Land Northward was covered with inhabitants.” It is doubtful that this rapid population increase could have been accomplished by direct descendants of the Jaredite colony alone. It could easily have been done by assimilating with indigenous (Olmec) peoples.