Archaeological evidence including stone tools found in the Nam Jook River Valley in Vieng Phoukha and cliff paintings near Nale suggest that Luang Namtha Province was inhabited as early as 6,000 years ago.
The first local written account of the province’s history appears in the Xieng Khaeng Chronicles that recount the founding of Xieng Khaeng on the banks of the Mekong River in the early 15th century by Chao Fa Dek Noi, a Tai-Lue that originated in the court of Chiang Rung. Xieng Khaeng grew into a modest principality that later found itself under the influence of the Lanna Kingdom of Northern Thailand until the early 16th century and then become a Burmese vassal from the mid 16th to the early 19th century. Beginning in the first half of the 19th century, Xieng Khaeng fell under Siamese domination and suffered from numerous conflicts. In 1885 Chao Fa Silinor eventually led more than 1,000 Tai-Lue subjects to what is present day Muang Sing for both strategic military reasons and in search of more expansive agricultural land.