The only named river in Book of Mormon lands is Sidon; other unnamed rivers are mentioned only in the (Jaredite) Land Northward:
3 …there were an exceedingly great many who departed out of the land of Zarahemla, and went forth unto the land northward to inherit the land.
4 And they did travel to an exceedingly great distance, insomuch that they came to large bodies of water and MANY RIVERS. (Helaman 3)
4 And it came to pass that we did march forth to the land of Cumorah, and we did pitch our tents around about the hill Cumorah; and it was in a land of many waters, RIVERS, and fountains; and here we had hope to gain advantage over the Lamanites (Mormon 6)
Rivers not included:
- Old World rivers
- Figurative expressions