Southern Thailand is on the Malay P

Southern Thailand is on the Malay Peninsula, with an area of around 70,713 km2 (27,302 sq mi), bounded to the north by Kra Isthmus, 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 in Surat Thani, which together with the Phum Duang in Surat Thani drains more than 8,000 km2 (3,100 sq mi), more than 10% of the total area of Southern Thailand. Smaller rivers include the Pattani, Saiburi, Krabi, and the Trang. The biggest lake of the south is Songkhla Lake (1,040 km2 (400 sq mi) altogether). The largest artificial lake is the Chiao Lan (Ratchaprapha Dam), occupying 165 km2 (64 sq mi) of Khao Sok National Park in Surat Thani.