Sirmaur district is a district of Himachal Pradesh state with an administrative headquarters located at Nahan town. There are many interesting stories associated with the origin of the name, “Sirmaur”. According to one story the state got its name as Sirmaur since it held the senior most position amongst the princely hill states. Another view is that long years back Sirmaur was the capital of the state and that’s why the state was also called after the name of its capital. But, the origin of the word ‘Sirmaur’ is still not cleared. As per the third version, the place was established about 1090 by Raja Rasaloo of Jaisalmer and he had an ancestor whose name was Sirmour, belonged to the Rasaloo family. Later it became a princely state of 11 Gun Salute in British India. Earlier the place was also popularly known as Nahan because Nahan was a significant town of the place. At that time the place of Sirmaur was under the rule of the chiefs of Rajput lineage, who used the title "Maharaja". The region of Sirmaur was ruled by numerous local Rajas such as Raja Shamsher Prakash, Raja Surender Vikram Prakash, Raja Amar Prakash and many more during different period of time.

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Geographically, the district lies at 30°73'N latitude and 77°29'E longitude. The maltitude in the district is 1555 m. In the year 2021, there was a total 49.33% forest area of total geographical area. The district encompasses a geographical area of 2,825 sq kms and it is bounded by Shimla district on the North East, Solan district on the North West, Uttarakhand on the South East and Haryana on the South West. The climate of the district remains pleasant throughout the year. Most of its rainfall occurs in the monsoon season. The actual rainfall in the district was 1727.1 mm in the year of 2021-22.

Administration wise, the district is divided into 10 sub-districts, 3 towns and 976 villages. The administrative language in the district is Hindi.

According to 2011 census the district has a population of 5,29,855 out of which 2,76,289 are males and 2,53,566 are females. The district has a sex ratio of 918 (females for every 1000 males). During the year 2001-2011 the population growth rate in the district was 15.54% including 14.50% are males and 16.69% are females. As per 2011 census the major religion in the district is Hindu with 89.99% of the total population. The population density in the district is 188 (persons per sq. km.). As per 2011 census the principal language in the district is Hindi with 94.10%. In the year 2020 the number of live births in the district was 7,500 out of which 3,890 were males and 3,610 were females. In the same year the number of deaths in the district was 2,741 out of which 1,664 were males and 1,077 were females.

Agriculture is the backbone of the economy of the district. Most of the lands in the district are use for agricultural purposes. More than half of its population are engaged in agriculture in order to earn their livelihood. The chief agricultural products in the district are apple, mango, tomato, potato, ginger, peach, etc. The adoption of the new agricultural technologies amongst the famers of the district helps to increase the production of various agricultural items. Every year a huge chunk of revenue comes from the agricultural products in the district helps in its economy to a great extent. Industrially also the district is quite well developed. Some of its prominent industries are Malwa Cotton Spinning Mills, Ranbaxy Laboratories, Taral Metals Ltd, Himalya International Ltd, Him Neel Breweries, Saboo Cylinders, Birla Yamaha, Pashupati Spinning and Weaving Mills, Ruchira Paper Ltd, Lime Chemicals, etc. Sometime the tourism sector of the district contributes in its economy remarkably as well. Sataun in this district is the largest limestone market of South East Asia. It is one of the two most backward districts of Himachal Pradesh that is receiving funds from the Backward Regions Grant Fund Programme. In the year 2015-2016 the gross domestic product in the district was Rs. 9,42,670 lakh at current price in the year 2011-2012. In the year 2015-16 the net domestic product in the district was Rs. 8,03,191 lakh at current price in the year 2011-2012. In the year 2015-2016 the Per Capita Income was in Rs. 1,45,597 at Current Price in the year 2011-2012.

The district is well known as an abode of several reputed educational institutions. It provides a platform for higher education. Some of its recognised educational institutions are Jawahar Navodaya Vidyalaya, Career Academy Senior Secondary School, Carmel Convent School, Army Public School, A.V.N public school, D.A.V Public School, Sirmour Public School, Holy Heart Public School, Silver Bells Public School, etc. As per 2011 census the literacy rate in the district is 78.8% out of which 85.61% are males and 71.36% are females. The number of literates in the district is 3,62,645 including 2,05,617 are males and 1,57,028 are females.

The district has several centres of attraction which allures many travellers from different parts of the country as well as world. The Jaitak hill, located in the annals of Sirmaur is the historically significant place where an important battle was fought between the British forces and the Gurkhas. Jaitak name is applied to a peak or perhaps two peaks. Haripur Dhar is a range of mountain where a fort was built by the rulers of earlier Sirmaur State. Nahan, the district headquarters of the place was founded by Raja Karam Parkash in 1621 AD. Its climate remains pleasant almost throughout the year. It has several renowned temples and tanks which allures pilgrims from far off places. Some other notable places of interest in the district are Renuka, Paonta Sahib, Churdhar Peak, Rajgarh, Shivalik Fossil Park, Trilokpur and many more.