Like most gangs, they can be seen taking part in activities such as stagecoach robberies and lynchings, and seem to have their headquarters in the Gaptooth Breach mine.
Gang members have characteristics similar to those of Seth Briars (low morals, worn clothing, poor hygiene, etc.). Marston can unlock the Treasure Hunter Outfit to dress as a member of the gang, allowing him to enter their hideout without being attacked.
The following is a list of known members of the Treasure Hunters gang:
- Clark Hatfield
- Digby Haskins
- Fletch Hillard
- Harlan Forbes
- Lester Dugan
- Mickey Brunson
- Roscoe Duffy
- Stanley Mund
- Wade Bassett
Note: While the above-mentioned Treasure Hunters have names, there are also two unnamed Treasure Hunters who both appear in multiplayer and singleplayer. The first one uses the same character model as Quick Tom Candle while the second uses the same model as Guy Percival.
- Some of the Treasure Hunter's outfits bear a resemblance to the outfit Henry Moon wore while mining for gold in the 1978 film, Goin' South.
- Unlike most other gangs, the Treasure Hunters gang appear to also partake in non-criminal activities. If the player enters Gaptooth Breach while wearing the Treasure Hunter Outfit, they can witness gang members going about their daily work prospecting and mining the rock for ores.
- The Treasure Hunters will appear in the Gaptooth Breach hideout before completion of the mission Man is Born Unto Trouble, and will not act aggressively towards Marston. However, the player needs to have completed most of the storyline missions up to this point before they will spawn.
- The Treasure Hunter's Gang is the only gang in New Austin, who has an unknown leader.
- Stanley Mund and Fletch Hillard are the only gang members in singleplayer that do not appear at Gaptooth Breach after the mission Man is Born Unto Trouble.
- Digby Haskins and Stanley Mund are the only obese gang members of The Treasure Hunters.
- The member who uses Guy Percival's character model in the singleplayer is the one that has the Springfield Rifle, during the Gaptooth Breach hideout.