The School of Necromancy is housed in an underground complex beneath the city of Andorhal. The School of Necromancy is a sprawling subterranean labyrinth akin to the Undercity on a much smaller scale. Undead horrors, necromancers, dark warlocks, and Damned Cultists haunt the tunnels.
Darkmaster Gandling, a mummified wretch, teaches students how to raise the dead in the Lich King's name. Formerly a Dalaran wizard, he betrayed his masters for dark power and now revels in undeath. His graduates go on to Stratholme, the Scourge's capital in the Eastern Plaguelands. Apparently, a sister school to the Scholomance exists under Caer Darrow.
This may have been developed into the Scholomance under Caer Darrow. However, the info was re-established in World of Warcraft: The Roleplaying Game which was published after the release of the World of Warcraft MMO. This may have been in error; the reference to Darkmaster Gandling as a teacher at this academy (when he is, in fact, the headmaster of the Scholomance) is at least one indication of this (although, it is possible he could have been promoted from teacher at the school to headmaster of the Scholomance).
Note, the reference to Darkmaster Gandling is only made in Lands of Conflict, but not in World of Warcraft: The Roleplaying Game, the latter only refers to the school. It should also be noted that the term Scholomance does literally mean "School of Magic", and according to WoW Map Viewer the name for the Scholomance instance is School of Necromancy.