After the sad news that the majority of the people had rejected both the Nephite nation and the Nephite religion, Mormon ends with recognizing that there were still some who believed, and that there was a continuation of the mission of the gospel. People who repented were baptized, leaders and teachers were appointed. The Nephite nation may have been dissolved, but many remained who continued to believe in the Nephite gospel.
Mormon does not tell us where these people were. With the difficulties of travel in the ancient world, and the animosity that Mormon indicated was endemic to the separated tribes, it would appear to be reasonable that these believers would also desire to be together as a community rather than mixed in with people who would persecute them.
A movement of this people into the land Bountiful may explain why that was the location mentioned where the resurrected Savior appeared.
Mormon ends a chapter at this point. The nature of the text to this point suggests that Mormon intermingled information from the large plates (represented by the annalistic listing of the years) as well as Nephi’s personal record (represented by the favorable recording of Nephi’s actions). In the next chapter, however, that shift will be complete. Thus, Mormon creates a chapter break between these chapters and the next, which will begin the crucial story of the Book of Mormon.