Wikia

Instance	Level	Location	Notes
Baradin Hold	Raid	Tol Barad
Bastion of Twilight	Raid	Twilight Highlands ^{[34, 78]}	Entrance found atop the Twilight Citadel.
Blackrock Caverns	80-83	Blackrock Spire 48,69	From the south entrance of the mountain: Turn right in the main chamber, then first tunnel on your right, turn right at the piles of rubble (easy to miss). If you go up the ramp you've gone too far.
Blackwing Descent	Raid	Burning Steppes ^{[23, 26]}	Fly up to Nefarian ledge ^{[27, 25]} .
Grim Batol	85	Twilight Highlands ^{[19, 54]}	If on foot, only accessable from the northern Wetlands entrance ^{[80, 48]} .
Halls of Origination	85	Uldum ^{[72, 52]}	Enter the pyramid from the east.
Lost City of Tol'vir	84-85	Uldum ^{[61, 64]}
Stonecore	81-84	Deepholm ^{[47, 52]}	Fly about half-way up the western outside of the spire.
Throne of the Four Winds	Raid	Uldum ^{[38, 81]}
Throne of the Tides	80-83	Abyssal Depths ^{[71, 29]}	Swim down into the vortex. Once inside The Abyssal Maw, the instance is to your north-east.
Vortex Pinnacle	81-85	Uldum ^{[77, 84]}

Cataclysm instance locations