Mae Hong Son (also Mae Hong Sorn) is one of the northern provinces. It is also the westernmost province of Thailand, bordering Myanmar, the Salween River forms part of the boundary. Located between several mountain ranges it enjoys a cooler climate then most of the other areas of Thailand. The province has the lowest population density of all the provinces of Thailand, most of the population are members of the hill tribes Hmong, Yao, Lahu, Lisu, Akha, Karen, and Shan.