Suratthani It is the largest and most important province of the South, located 644 kms. from Bangkok. It occupies an area of 12,891.5 square kilometers bordering on Chumphon and the Gulf of Thailand to the north, Nakhon Si Thammarat and Krabi to the south, Phangnga and Ranong to the west and the Gulf of Thailand and Nakhon Si Thammarat to the east.