Complex sentence: A significant population of Navajo still resided along the Little Colorado and Colorado Rivers as well as on Naatsisʼáán (Navajo Mountain), never suffering in the concentration camps at Hwéeldi (Ft. Sumner).
Split into simpler sentences: A significant population of Navajo still resided along the Little Colorado and Colorado rivers as well as on Naatsisʼáán (Navajo Mountain). They had never lived in the concentration camps at Hwéeldi (Ft. Sumner).