Surin is a province in Isaan, North East Thailand. Koh Surin is a national park run group of islands reached from Phang Nga or Ranong provinces, north of Phuket. Surin Beach is a beach in Phuket, next to Surin town. So you need to go to the Phuket forum.
Similarly Angthong is a province in central Bangkok, and Angthong Marine Park is a group of islands near Koh Samui.