LV-426, or "Acheron" was the desolate planet shown in both Alien & Aliens. But as Ripley stated "it was not indigenous, it was an alien ship it did not come from there" meaning that LV-426 was not the Aliens' home planet.
The actual fact that they even have a home planet in the first place is questionable, if the Space Jockey creation theory is correct, then the Aliens would not have a home planet to begin with, although if that theory is incorrect, then it's all up to guesswork really