Blackrock Deeps Entrance. To pick up this quest go to Stormwind City. Another massive case solved just days.

The depths have many sections including a prison Shadowforge City a vast capital of the Dark Iron dwarves and the Grim Guzzler tavern. The NPC youre meetingBurt Macklynis just before the entrance to the BRD dungeon and to the left. The deeps are comprised of a series of watery caverns leading deep to a temple devoted to the Old Gods.
Neutral Blackrock Depths Quests - Early Bosses.
However there are not two different portals so when you are queued up for either you will start out in the main entrance. The NPC panel has been upgraded to allow some specific filtering you can. The depths have many sections including a prison Shadowforge City a vast capital of the Dark Iron dwarves and the Grim Guzzler tavern. Blackrock Depths is the largest instance in the game.