Mountains of Flame
The Mountains of Flame are a mountain range in seen on the northern portion of the Outland map in Warcraft III: The Frozen Throne. As seen from the map, it is near where the Black Citadel was located.
There are no locations in Outland in World of Warcraft carrying these mountains' name. Moreover, it's difficult to estimate where they in any case would have been located. In the TBC "Behind the Scenes" DVD, one of the designers stated that players had only visited Hellfire Peninsula during Warcraft III. As such, the Mountains of Flame can be assumed to have been part of the northern Hellfire Peninsula - possibly another name for the Throne of Kil'jaeden. However, the Black Citadel - which in Warcraft III was located in Hellfire Peninsula - was later retconned to actually be the same as the Black Temple which is located in Shadowmoon Valley. As such, some speculate that the Mountains of Flame could be whats now known as the Hand of Gul'dan instead.