PRACHUAP KHIRI KHAN
The long coast of the Gulf of Thailand has many sandy beaches, the most famous one being at Hua Hin, which has been a popular resort since King Prajadhipok (Rama VII) built a summer palace there. From the coast the land quickly rises into the Tanaosi Range, the mountain chain that forms the border with Myanmar.
https://www.tourismthailand.org/About-Thailand/Destination/Prachuap-Khiri-Khan