Boo Woods

Boo Woods is a location on the Mushroom Planet and was featured in Luigi's Mansion. Boo Woods is extremely large and full of creepy looking trees, E. Gadd's lab is found here along with the mansion Luigi won. What is possibly Boo Woods is in Mario Kart DS, in this game it has a large swamp and the trees can move around. As the name implies, Boos haunt this area along with their leader King Boo.

Young E. Gadd also, mentions Boo Woods in Mario & Luigi: Partners In Time. After his lab is destroyed by the volcano he says he will now move to Boo Woods.

Boo Woods is extremely similar looking to Forever Forest which means that Boos prefer dark spooky woods.