Kinnaur district is a mountainous district located in the northeast part of the state of Himachal Pradesh, India. Kinnaur district borders Tibet (China) to the east, the state of Uttarakhand to the south, Shimla district to the southwest, Kullu district to the west, and Lahaul and Spiti district to the north. The administrative headquarters of the district is at Reckong Peo. Kinnaur district's south-western parts are part of the historical Mahasu region.