Sirmaur district is the southernmost district in the Himalayan state of Himachal Pradesh, India. It is largely mountainous and rural, with 90% of its population living in villages. The district capital is the town of Nahan. Some other towns include Paonta Sahib, Lana Palar, Tuheri, Bhawan, Sirmaur, Shamra, UchaTikker and Suketi - the last being known for Shivalik Fossil Park. Culturally, it is a part of the historical Mahasu region.