Northrend Dungeon Hero

Here's a list of where you can find each of the instances.

Although they can be soloed at level 85, be aware of the 5/hour instance limit.

Northrend
Heroic: The Oculus - Borean Tundra
Heroic: The Nexus - Borean Tundra
Heroic: Ahn'kahet: The Old Kingdom - Dragonblight
Heroic: Azjol-Nerub - Dragonblight
Heroic: Violet Hold - Dalaran
Heroic: Halls of Stone - The Storm Peaks
Heroic: Halls of Lightning - The Storm Peaks
Heroic: Gundrak - Zul'Drak
Heroic: Drak'Tharon Keep - Grizzly Hills
Heroic: Utgarde Keep - Howling Fjord
Heroic: Utgarde Pinnacle - Howling Fjord

Kalimdor
Heroic: The Culling of Stratholme - Tanaris

Most all of the Northrend Heroic Dungeons can be solo'ed by a well-geared (iLvl 380+) 85. The only real peril you may find is when fighting [npc=27656] in [zone=4228]. This is mainly due in part to the fact your stats mean very little if anything, instead you rely on the drake you're riding to do the deed.

+1 if you're here because of Heroic Solo'ing.

This will require you to kill every single boss in every single heroic instance in Northrend to get. Each requirement for this achievement is also a achievement, so you will be rewarded quite a bit of points for this.

Edit: You will receive a combined total of -140- Achievement Points for completing this.