Khammouane or Khammouan is a province of Laos, located in the center of the country. Its capital lies at Thakhek.
Khammouane Province covers an area of 16,315 square kilometres (6,299 sq mi) and is mostly of forested mountainous terrain. The province is bordered by Bolikhamsai Province to the north and northwest, Vietnam to the east, Savannakhet Province to the south, and Thailand to the west. Many streams flow through the province to join the Mekong River. The vast forests of the Nakai-Nam Theun Biodiversity Conservation Area are an important watershed that feed many Mekong tributaries as well as form the catchment area for Nam Theun 2, the largest hydropower project in Laos. The Xe Bangfay, Nam Hinboun and Nam Theun are the main rivers of the province.
Khammouane, meaning “happy gold”, is believed to have been named after the gold deposits found in the area hundreds of years ago. The province’s history dates back as early as the 6th-8th centuries when the region was part of the Sikhottabong Kingdom. Remnants of the ancient civilization include the Great Wall (Kampeng Nyak), Meuang Phone Stupa, and Sikhottabong Stupa-one of the most sacred in Laos. The province has many remaining buildings that date to the colonial period, especially in the provincial capital of Thakhaek. There is an abandoned railway track that was originally planned to connect Laos with Vietnam but was never finished. Today the only evidence of this endeavor is an old railway bridge over the Nam Don River.
Khammouane is a land of rugged karst mountains which were once the refuge of a succession of ethnic groups fleeing the Haw invasions in the north during the 19th century. The famed Mu Gia pass at the end of route 12 was one of the main transit points of the legendary Ho Chi Minh Trail during the Indochina Wars. This dreamlike landscape has served as a sanctuary for a number of wild animals that were unknown to scientists until the 1990s. The khan you, a small rodent-like creature the size of a small squirrel was found in Khammouane in the early 21st century and possibly will be the last remaining mammalian family to be described on earth.