From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Diablo Desert (ヤムチャ の 荒野, Yamucha no Arano; Literally meaning "Yamucha's Wilderness") is a giant desolate desert on Planet Earth.
The Diablo Desert was the territory of Yamucha and Puar. They robbed people of their money or Hoi Poi Capsules. The Diablo Desert was near Fire Mountain and was also where Pilaf's Castle and the Rabbit Gang's Town was located. One unique feature from the rest of the world was that many big mushroom trees grew here.
Yamucha ambushed Oolong and Son Goku here in "Yamcha the Desert Bandit", but he was scared off at the sight of a girl, Bulma Brief. In the next episode, Oolong had a House-Wagon set up in the desert to camp in. Yamucha destroyed it the next morning and followed them out of the desert on the rest of their journey.
Dragon Ball Z
Yamucha returned to the Diablo Desert after the events of the Kid Buu Saga to live his old life here again, though presumably not becoming a bandit again.
Dragon Ball GT
The Diablo Desert was surrounded by a giant stone wall in Dragon Ball: Curse of the Blood Rubies.
The Diablo Desert appeared in Dragon Ball: Plan to Eradicate the Super Saiyans.
Diablo Desert is the third level in Dragon Power. Yamucha steals the Dragon Balls and you must go through various caves to collect the Dragon Balls again. You then fight Yamucha at the end of the level.
Diablo Desert is the third level in Dragon Ball: Advanced Adventure.
A noon, evening, and night version of Diablo Desert is unlockable in Dragon Ball Z: Budokai Tenkaichi 3.
- Oolong mentions in "Boss Rabbit's Magic Touch" that Bulma did not let them stop at the last town for gas, meaning a town other than the Rabbit Gang's Town exists in the Diablo Desert.