Mae Hong Son province, also spelled Maehongson, Mae Hong Sorn or Maehongsorn, is one of Thailand's seventy-six provinces. It lies in upper northern Thailand and is the westernmost province. Neighboring provinces are Shan State of Myanmar, Chiang Mai and Tak. To the west, the province borders Kayin State and Kayah State of Myanmar. Mae Hong Son's nickname is "the city of three mists".