Thunder Falls is a waterfall in west Elwynn Forest that leads into Mirror Lake. A steep path to the right of Mirror Lake Falls leads up to a small Defias camp that has level 8-10 Defias Bandits. If the river is followed it will eventually wind into a waterfall that empties near the border of Westfall. The bottom of the waterfalll can be reached from above via careful navigation of the hilly terrain.
Thunder Falls is quite unusual in the sense that it is a double-sided waterfall. The Falls are fed by another, inaccessible waterfall on some mountains on the north of this plateau.
There is no real history behind Thunder Falls. Most likely it was a small residential place where a family lived, and got overrun by Defias Bandits.