is a distinct region of Thailand, connected with the Central region by the narrow Kra Isthmus.
- Chumphon (ชุมพร)
- Krabi (กระบี่)
- Nakhon Si Thammarat (นครศรีธรรมราช)
- Narathiwat (นราธิวาส)
- Pattani (ปัตตานี)
- Phang Nga (พังงา)
- Phattalung (พัทลุง)
- Phuket (ภูเก็ต)
- Ranong (ระนอง)
- Satun (สตูล)
- Songkhla (สงขลา)
- Surat Thani (สุราษฎร์ธานี)
- Trang (ตรัง)
- Yala (ยะลา)
Southern Thailand is located on the Malay Peninsula, bounded to the north by Kra Isthmus as the narrowest part of the peninsula. The western part has steeper coasts, while on the east side river plains dominate. The largest river of the south is the Tapi, which together with the Phum Duang drains more than 8,000 km², more than 10% of the total area of Southern Thailand. Smaller rivers include the Pattani, Saiburi river and the Trang. The biggest lake of the south is the Songkhla lake (1,040 km² altogether), the largest artificial lake is the Chiao Lan (Ratchaprapha dam) with 165 km² within the Khao Sok national park.
Running through the middle of the peninsula are several mountain chains, with the highest elevation at the 1835 m high Khao Luang in the Nakhon Si Thammarat Province. Ranging from the Kra Isthmus till the Phuket island is the Phuket chain, which connects to the Tanao Si Mountain Range further north. Almost parallel to the Phuket chain but 100km to the east is the Nakhon Si Thammarat or Banthat chain, which begins with the Samui island and ends at the Malayian border at the Ko Ta Ru Tao archipelago. The border to Malaysia is formed by the San Kala Khiri range, sometimes subdivided into the Pattani, Taluban and Songkhla chain. At the border to Malaysia begins the Titiwangsa chain.
The Malay peninsula was settled since prehistoric times. Archeological remains were found in several caves, some used for dwellings, other as burial sites as well. The oldest remains were found in Lang Rongrien cave dating 38,000 to 27,000 years before present, and in the contemporary Moh Khiew cave.
In the first millennium Chinese chronicles mention several coastal cities or city-states, however they don't give exact geographical location, so the identification of these cities with the later historical cities is difficult. The most important of these states were Langkasuka, usually considered a precursor of the Pattani kingdom; Tambralinga, probably the precursor of the Nakhon Si Thammarat kingdom, or P'an-p'an, probably located at the Bandon Bay. The cities were highly influenced by Indian culture, and have adopted Brahman or Buddhist religion. When Srivijaya extended its sphere of influence, those cities became tributary states of Srivijaya.
After Srivijaya lost its influence, Nakhon Si Thammarat became the dominant kingdom of the area. During the rule of King Ramkhamhaeng the Great of Sukhothai, Thai influence first reached Nakhon Si Thammarat. According to the Ramkhamhaeng inscription Nakhon was even a tributary state of Sukhothai. During most of the later history Nakhon was a tributary of Ayutthaya.
The deep south belonged to the Malay sultanates of Pattani and Kedah.