Pengkalan Hulu, formerly known as Kroh or Keroh, is a town and a mukim in Hulu Perak District, Perak, Malaysia, bordering Thailand and Keda…Pengkalan Hulu, formerly known as Kroh or Keroh, is a town and a mukim in Hulu Perak District, Perak, Malaysia, bordering Thailand and Kedah. The nearest town on the Thailand side is Betong in Yala province.