Verse 10 provides some geographical information, but information which is dissimilar to previous discussions of the geography. There is still a land south and a land north. There is still Zarahemla in the center. What has shifted is perspective. Mormon gives us no way to know why he calls the land to the south the land of Lehi as opposed to the land of Nephi. Perhaps the previous designations were always to the city of Nephi and the surrounding lands. Perhaps the greater land, now inhabited by righteous Lamanites, is to be included in the sacred geography. In that case, the label “land of Lehi” would be used to include the Lamanite lands. The point of verses 1 through 9 of this chapter has been to include the Lamanites along with the Nephites in mutual prosperity.
The land to the north is Mulek, which makes a distinction between the land of the Jaredites and the original land of the Mulekites. Since both are in the north, both will likely have some negative associations, and Mormon appears to suggest that it is the descendants of the Mulekites who often foment dissent among the Nephites, desiring for a change in religion and a return to monarchy.
Since the implication of this geography is positive, it is also likely that the land of Mulek is included in the north so that it can have a more positive connotation than the desolation of the Jaredites.