According to Joseph Smith, "The whole of America is Zion itself from north to south, and is described by the prophets, who declare that it is the Zion where the mountain of the Lord should be . . ." [Teachings of the Prophet Joseph Smith, p. 362]
Brigham Young said the following: "And what is Zion? In one sense Zion is the pure in heart. But is there a land that ever will be called Zion? Yes, brethren. What land is it? It is the land that the Lord gave to Jacob, who bequeathed it to his son, Joseph, and his posterity, and they inhabit it, and that land is North and South America. The children of Zion have not yet much in their possession, but their territory is North and South America, to begin with. As to the spirit of Zion, it is in the hearts of the Saints of those who live and serve the Lord with all their might, mind and strength!" [Discourses of Brigham Young, pp. 119-120] [See the commentary on 3 Nephi 20:14, 22; 21:4]