Sirmaur District is the most populated south-eastern district of Himachal Pradesh. It is largely mountainous and rural area with 90% of its population living in villages. It includes the towns of Nahan as well as the Shivalik Fossil Park at Suketi, where fossils over 85 million years old have been found.
Solan District is one of the twelve districts of Himachal Pradesh state in northern India. Solan town is the administrative headquarters of the district. The district occupies an area of 1936 km.sq. Solan District came into existence at the time of the reorganization of the districts of the State on 1st September, 1972. Solan district was carved out of Solan and Arki tehsils of the then Mahasu district and tehsils of Kandaghat and Nalagarh of the then Shimla District. Solan district is divided into four Sub-divisions comprising of Solan and Kasauli tehsils. The history of Solan District goes back to the era of Pandavas in Mahabharata Era. According to the Hindu mythology, Pandavas lived here during their exile. In 1815, The British East India Company won Baghat state which is now called Solan from the Gurkhas. The Gurkha fort or Arki Fort is still standing tall on a mountain near to Solan city and it is one of the popular historic tourist attractions of Solan. The town has been a capital of the princely Baghat State. Solan can be called a British town as primarily a cantonment was built here in the late 19th century by the British East India Company, which after 1857, became the British Government in India. The Solan cantonment is still the best and the most well planned part of this area hence buildings are made in a planned manner of Gothic and Roman architecture. The church in Solan cantonment is a heritage building with beautiful wooden and stone carvings. It has an elegant sloping roofs plus arches evocative of the British architecture.