Kayah State is an autonomous state of the Republic of the Union of Myanmar, formerly known as Karenni State. It is bordered by Thailand to the east, Shan State to the north, and Karen State to the west. It covers an area of 12,000 square kilometers and has a population of about 320,000 (2019). It is divided into two districts, with Bago as its capital. The territory has a mostly highland climate and is inhabited mostly by the Kayah ethnic group, which belongs to the Kayah branch of the Tibetan-Burman language family of the Sino-Tibetan language family. Since 1948, Kayah local forces have been engaged in guerrilla warfare against the Myanmar central government forces.