Because chapter 7 is addressed to the Lamanites, many people ask who are the Lamanites in today's world.
The Lord specifically identified them in D&C 28, 30 and 32. These are the Native American Indian tribes living in New York, Ohio, and Missouri (tribes who had been forced west from their native lands around the Great Lakes).
Strangely, but not surprisingly given Mesomania, the manual does not reference D&C 28, 30, and 32. Instead, it says this:
Read and discuss Mormon 7, which contains Mormon’s words to the latter-day descendants of Lehi. You may want to explain that latter-day descendants of Lehi are found among the people of North, Central, and South America and the Pacific Islands.
As the lesson manual points out, other prophets have commented on the presence of Lamanites in Latin America. I discuss that here:
The important point to remember is that the presence of Lamanite ancestry among people living in Latin America today has nothing to do with the location of Cumorah 1600 years ago. Cumorah is in New York. Lamanites have interacted with other indigenous people throughout Latin America and the Pacific. While DNA shows that the Native Americans in the northeastern U.S. have non-Asian origins (unlike most native peoples in Latin America and the Pacific), there's no reason to think Lamanite ancestry is more widely dispersed, albeit in relatively low concentrations outside the northeastern U.S.