Karen-Ni was the country of the Red Karens, a collection of small states, formerly independent, but was the feudatory to Burma (Myanmar). The states were bounded on the north by the Shan states of Mong Pai, Hsatung and Mawkmai. On the east, it was bounded by Thailand on the south by the Papun district of Lower Burma, and on the west a stretch of mountainous country, inhabited by the Bre and various other small tribes. During British rule in Burma, it had a guard of military police, which was posted at the village of Loikaw.
The Karenni States is the name formerly given to the three states of Kantarawadi (pop (1931) 30,677), Kyebogyi (pop (1931) 14,282) and Bawlake (pop (1931) 13,802), located south of the Federated Shan States and east of British Burma.
The British government recognized and guaranteed the independence of the Karenni States in an 1875 treaty with Burmese King Mindon Min, by which both parties recognized the area as belonging neither to Burma nor to Great Britain. Consequently, the Karenni States were never fully incorporated into British Burma. The Karenni States were recognized as tributary to British Burma in 1892, when their rulers agreed to accept a stipend from the British government. In the 1930s, the Mawchi Mine in Bawlake was the most important source of tungsten in the world. The Constitution of the Union of Burma in 1947 proclaimed that the three Karenni States be amalgamated into a single constituent state of the union, called Karenni State. It also provided for the possibility of secession from the Union after 10 years. In 1952, the former Shan state of Mong Pai was added, and the whole renamed Kayah State, possibly with the intent of driving a wedge between the Karenni and the Karen, both of whom were by now fighting for independence.