Beanbean Borderlands

From the Super Mario Wiki

Beanbean Borderlands is an outlying area in Mario & Luigi: Superstar Saga. Mario and Luigi crashed here, along with a couple of Koopa Troopas, after Fawful damaged the Koopa Cruiser. The Mario Bros. had to first cross into the Beanbean Kingdom's side through a building patrolled by the Border Bros.. When they pass, the Mario Bros. end up in Stardust Fields. Later in the game, Cackletta and Fawful retreated here after the Mario Bros. defeated her at the Woohoo Hooniversity. At the same time, Bowser landed here after the Beanstar broke into pieces. Ironically, Bowser just remembered who he was and was then possessed by Cackletta.

The Beanbean Border is interestingly not part of the Beanbean Kingdom. The Beanbean Borderlands are easily confused with Stardust Fields due to the fact that they look very similar.