Shortly after arriving at their promised land, father Lehi, sensing he was about to die, appointed Nephi to be the colony leader.
Nephi's brothers, Laman and Lemuel, rebelled against this and their father's teachings and desired to kill Nephi.
Therefore, Nephi and those who would follow the teachings of their father, departed into the wilderness and traveled to a place they called the land of Nephi and established a city called Nephi.
This video locates, by using Book of Mormon scriptures, the city of Nephi. The city and surrounding area is described in Mosiah 11:12-13.
There was a fortress on a hill to the north of the city and inside the fortress was a tower. The city, the fortress and the base of the tower are still available to see.