The expedition sent through the Dark Portal by Thrall has built a stronghold in Hellfire Peninsula. Thrallmar serves as a base of operations for much of the Horde's activities in Outland.

Reputation

Reputation for Thrallmar up to Honored is relatively easy to earn. Even the easiest quests (those that take you from one quest giver to the next up the road, for example) can yield 75 reputation points, while those that require some effort to complete typically yield 250 reputation points or more. Some group quests that involve killing an elite can yield as much as 1000 reputation points.

Neutral through Friendly
Reputation from mobs in Hellfire Ramparts and Blood Furnace stops at 5999/6000 friendly. One option is to grind reputation via Ramparts and Blood Furnace runs to 5999/6000 before doing any Thrallmar quests outside the instances, as those continue to yield reputation up to Exalted.

Also, the level 63 mobs outside Hellfire Citadel (on the path) give you 5 reputation each.

Friendly through Honored
Players that enjoy PvP can earn Thrallmar reputation through the daily quest Hellfire Fortifications. This quest awards 70 silver and 150 Thrallmar reputation, but can only be completed once a day and counts towards your 25 daily quest limit. Completion of this quest also yields three Mark of Thrallmar, which are used as currency for various types of items and gear when turned into Battlecryer Blackeye and the Horde Field Scout in Thrallmar and near Zabra'jin in Zangarmarsh respectively.

Blood Furnace and Ramparts instance runs will be your best bet for this reputation bracket, but they'll only take you to the end of Honored.
Revered to Exalted
From this point on, gaining reputation through Exalted requires one of two things:

• Access to Shattered Halls, one of the wings of Hellfire Citadel, which requires level 68.
• Doing Heroic versions of Hellfire Citadel dungeons.

Both of these give reputation until you reach Exalted status. A full clear of Shattered Halls nets you about 2000 reputation points, trash mobs generally yield 6 or 12 each, with up to 150 points from bosses. Heroic trash yields 15-25 points, with bosses worth more.

Tip: You can purchase Thrallmar Favor from Battlecryer Blackeye for use during instance runs to speed up the reputation (and experience) gaining process!