The Karen Hills, also known as Kayah-Karen Mountains, are one of the main hill ranges in eastern Burma. They are located at the SW corner of Shan State and in Kayah State, a mountainous region where the only relatively flat area is Loikaw, the capital. The southern end runs into Kayin State. One of the first all-weather roads in Burma was across the Karen Hills connecting Taungoo with Loilem.

Kayah State, or Karenni State, is a state of Myanmar. Situated in eastern Myanmar, it is bounded on the north by Shan State, on the east by Thailand's Mae Hong Son Province, and on the south and west by Kayin State. It lies approximately between 18° 30′ and 19° 55′ north latitude and between 96° 50′ and 97° 50′ east longitude. The area is 11,670 km2 (4,510 sq mi). Its capital is Loikaw. The estimated population in the 2014 Myanmar Census was 286,738, the smallest among Myanmar's seven states. It is inhabited primarily by the Karenni ethnic group, also known as Red Karen or Kayah, a Sino-Tibetan people.