The Tapi (or Tapee) river (Thai: แม่น้ำตาปี, RTGS: Maenam Tapi, Thai pronunciation: [mɛ̂ːnáːm tāːpīː]) is the longest river in southern Thailand. The river originates at Khao Luang mountain in Nakhon Si Thammarat Province, and empties into the Gulf of Thailand at Bandon Bay near the town of Surat Thani. It has a length of 230 kilometres (140 mi). The river was named on 29 July 1915, after the river Tapi in Surat, India, shortly after the town of Surat Thani was named after the town Surat in Gujarat, India.