Sahibzada Ajit Singh Nagar district is a district of Punjab with its administrative headquarters located at Sahibzada Ajit Singh Nagar city. The place is named after the eldest son of Guru Gobind Singh, Sahibzada Ajit Singh meaning "House of Sahibzada Ajit Singh". Earlier, its administrative headquarters was popularly known as Mohali but later it was officially changed to Sahibzada Ajit Singh Nagar. The previous name, Mohali means settlement and a village which was inhabited by Rajputs. After sometime it came under the rule of Sikhs and became a part of the Sikh Empire. The district was emerged as a separate district in the map of Punjab state on 12th February, 2012 and it is the 18th district of the state of Punjab, which formed next to its Pathankot district. This district was carved out of areas falling in the districts of Ropar and Patiala.

Geographically, the district lies at 30°70' N latitude, 76°72' E longitude and 316 m altitude. In the year 2021, there was a total 12.83% forest area of total geographical area. The district encompasses a geographical area of 1,094 sq km. and it is bounded by Rupnagar District on the North, Haryana on the South, Himachal Pradesh on the East and Fatehgarh Sahib District and Patiala District on the West. The climate of the district remains extremely hot during the summer season. Most of its rainfall occurs in the monsoon season. The actual rainfall in the district was 639.1 mm in the year of 2021-22.

Administration wise, the district is divided into 3 sub-districts namely Kharar tehsil, Sahibzada Ajit Singh Nagar Tehsil and Dera Bassi Tehsil. Moreover, it comprises 15 towns and 403 villages. The administrative language in the district is Punjabi.

According to 2011 census the district has a population of 9,94,628 out of which 5,29,253 are males and 4,65,375 are females. The district has a sex ratio of 879 females for every 1000 males. As per 2011 census the major religions in the district are Sikh and Hindu with 47.88% and 48.15% of the total population. During the year 2001-2011 the population growth rate in the district was 104.13% including 100.75% were males and 108.10% were females. The population density in the district is 909 persons per sq km. In the year 2020 the number of live births in the district was 15,043 out of which 7,724 were males and 7,319 were females. In the same year the number of deaths in the district was 7,994 out of which 4,894 were males and 3,100 were females. According to 2011 census the principal language in the district is Punjabi with 74.72%.

The economy of the district is mainly dependent on agriculture and industry. 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 adoption of the new agricultural technologies amongst the farmers of the district helps to increase the production of various agricultural items. Some of the prominent industries in the district are handloom, knitting, plywood, steel tubes, chemical paints, etc. These industries provide numerous job facilities to its natives. Every year a huge chunk of revenue comes from these industries helps in its economy to a great extent. In the year 2019-20 the gross domestic product in the district was Rs. 27,17,640 lakhs at current price and Rs. 21,26,895 lakhs at constant prices in the year 2011-2012. The net domestic product in the district during the period 2019-20 was Rs. 23,62,273 lakhs at current price and Rs. 18,42,972 lakhs at constant prices in the year 2011-2012. The Per Capita Income or NDDP, At Factor Cost during the period 2019-20 was Rs. 1,86,006 at current price and Rs. 1,45,116 at constant prices 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 Indian Institute of Science Education and Research, IIPM, Army Institute of Law, Shaheed Udham Singh College of Engineering and Technology, Chandigarh College of Education for Women, National Institute of Pharmaceutical Education and Research, etc. As per 2011 census the literacy rate in the district is 83.8% out of which 87.89% are males and 79.18% are females.

During the year 2018, there were 50,91,382 domestic tourists and 37,625 foreign tourists who visited the district. The district has several centres of attraction which allures many travellers from different parts of the country as well as world. Gurudwara Amb Sahib, a distinguished historical shrine is situated in sector 62, Mohali commemorates visit of 7th Guru of Sikhs, Guru Har Rai. The place also commemorates meeting of Guru Har Rai with his famous Sikh Labana trader named Bhai Kuram. Gurdwara Mata Sunder Kaur, another renowned historical Sikh Shrine managed by Buddha Dal is located in the sector 70, Mohali. It commemorates visit of Mata Sundri, along with Baba Deep Singh and Bhai Mani Singh. Fateh Burj, the tallest victory tower is situated in the city of Mohali, Punjab, India. The height of the tower is 328 ft and is dedicated to establishment of the Sikh rule in India in the year 1711. It is also popularly known as Baba Banda Singh Bahadur War Memorial. Gurudwara Singh Shaheedan, a famous shrine constructed in memory of martyrdom of Jathedar Baba Hanuman Singh, a Nihang Jathedar is situated in village Sohana, close to Sector 70. Some other notable places of interest in the district are Punjab Cricket Association Stadium, International Hockey Stadium, Sikh Ajaibghar and many more.