The Khen of Bhutan, numbering approximately 66,500 people, are Engaged yet Unreached. They are an indigenous people of south-central Bhutan's Zhemgang region with roots stretching back over 4,000 years, whose unification was marked by the 1655 construction of Zhemgang Dzong, and who maintain trade relations with the neighboring Bumthang yak herders. They mostly adhere to Tibetan Buddhism and Khengkha is their primary language.