Earlier the Chennai district was known as Madras district. It is the smallest of all districts in Tamil Nadu with its administrative headquarters located at Chennai city. The district is rich in almost every spheres likewise, industry, commerce, culture, education and economic. The origin of term Chennai is very confused. There are two different believes among the natives of the district regarding the origin of the name of the district- The first theory states that once upon a time there was a ruler named Damal Chennappa Nayagar, a Nayakar of Vandavasi who was a general under Sriranga Deva Raya of the Aravidu Dynasty. So, some people of the district believes that the word Chennai was derived from his name. Secondly, the another theory is that the district was named after the Chenna Kesava Perumal Temple. In Tamil language the word Chennai means face, which symbolized the temple as the face of the Chennai city. During the reign of Mahendravarman I, the Pallavas of Kanchi constructed the regions of Mahabalipuram and Pallavaram. Moreover, several kingdoms such as the Cheras, Cholas and Pandyas who ruled over the area earlier faced defeat in the hands of Mahendravarman I. During the period of an excavation some ancient coins dating to around 500 BC have been found in the city and its nearby areas as well. A portion of these findings belonged to the Vijayanagara Empire, who ruled the region during the medieval era. Then for the first time the Portuguese arrived there in the year 1522 and made a port named Sao Tome after the Christian apostle, St. Thomas, who is believed to have preached in the area between 52 and 70 CE. After sometime, in 1612, the Dutch established themselves near Pulicat, north of Chennai. Chennai as a separate district emerged in the map of Tamil Nadu in the year 1639. In 1996 the government of Tamil Nadu officially changed the name of the district from Madra to Chennai.

Krishnamachari Srikkanth, a former captain of the Indian cricket team and former chairman of the selection committee was born on 21th December, 1959 in Chennai. He represented Tamil Nadu in the Indian domestic circuit. Subbaraman Vijayalakshmi, an eminent Indian female chess player was born on 25th March, 1979 in the district. She is an International Master and has won more medals than any other player for India in the Chess Olympiads. She has won almost all national age group titles, including the senior title. In the year 2001 the Indian Government honoured her by the Arjuna Award.

Geographically, the district lies at 13°06'N latitude, 80°25'E longitude and 60 m altitude. In the year 2021, there was a total 7.24% forest area of total geographical area. The district occupies a geographical area of 175 sq. km. and it is bounded by the Bay of Bengal on the east and on the other remaining three sides by Chengalpattu and Thiruvallur Districts. The climate of Chennai is characterized as tropical wet and dry climate. Most of its rainfall occurs in the monsoon season. The actual rainfall in the district was 1964.6 mm in the year of 2021-22.

Administrative wise, the district is divided into 10 taluks namely Tondiarpet, Purasaiwalkam, Perambur, Ayanavaram, Egmore, Aminjikarai, Mylapore, Velachery, Mambalam and Guindy. There are 3 Lok Sabha constituencies and 16 Assembly constituencies in the district. The administrative language in the district is Tamil.

According to 2011 census the district has a population of 46,46,732 including 23,35,844 are males and 23,10,888 are females. The district has a sex ratio of 989 females for every 1000 males. During the year 2001-2011 the population growth rate in the district was 6.98% out of which 5.24% were males and 8.79% were females. As per 2011 census the major religion in the district is Hindu with 80.73% of the total population. The population density in the district is 26,553 persons per sq. km. According to 2011 census the principal language in the district is Tamil with 78.34%. In the year 2020 the number of live births in the district was 95,716 out of which 48,996 were males and 46,720 were females. In the same year the number of deaths in the district was 73,243 out of which 43,338 were males and 29,905 were females.

Textiles Mills in the district was set up during the British Period and today also these mills are the backbone of its economy to some extent. A remarkable part of the country's automobile industry is located in and around the city. For this very reason it is popularly called as the "Detroit of India". Some prominent automobile industries in the district includes Hyundai, Renault, Robert Bosch, Nissan Motors, Ashok Leyland, Daimler AG, Caterpillar Inc., Komatsu Limited, Ford, BMW and, Mitsubishi. In the year 2011-12 the gross domestic product in the district was Rs. 45,47,841 lakhs at current price and Rs. 31,55,060 lakhs at constant prices in the year 2004-2005. The net domestic product in the district during the period 2018-19 was Rs. 1,19,57,778 lakh at current price and Rs. 86,97,709 lakh at constant prices in the year 2011-2012. The Per Capita Income or NDDP, At Factor Cost during the period 2016-17 was Rs. 2,09,975 at current price and Rs. 1,68,785 at constant prices in the year 2011-2012.

The district has both the public and private schools with Telugu and English as the medium of instruction. A few schools with Urdu as medium of instruction are available in the district. Almost all the colleges in the district are affiliated with the University of Madras. Chennai. The city has also two CSIR research institutions namely Central Leather Research Institute and Structural Engineering Research Centre. As per 2011 census the literacy rate in the district is 90.18% including 93.7% are males and 86.64% are females. The total number of literates in the district is 37,76,276 out of which 19,68,079 are males and 18,08,197 are females.

Muthuvel Karunanidhi Stalin or M.K. Stalin, an illustrious Indian politician and the son of. famous politician of Tamil Nadu, Karunanidhi, was born on 1st March, 1953 in Chennai. After the 2006 assembly elections he became the Minister in the Government of Tamil Nadu with a portfolio of Rural Development and Local Administration. On 29th May 2009, he was nominated as Deputy Chief Minister of Tamil Nadu by Governor Surjit Singh Barnala. He is a member of Dravida Munnetra Kazhagam (DMK) political party.

Chennai, with its age old temples, mesmerising beaches and wonderful historical monuments, is the most well-liked destination for the travellers across the world. The Arignar Anna Zoological Park in the district is one of the largest zoological parks in the world which allures numerous tourists from far distance place. The city has two notable beaches- the Marina and Elliot. Guindy National Park, a protected area of Tamil Nadu, has a children's park and a snake park, which gained statutory recognition as a medium zoo from the Central Zoo Authority of India in 1995. The Parthsarthy Temple and Kapaleeshwar Temple were constructed in the 13th century are the best example of the Dravidians architectural skills. Mahabalipuram in Chennai is declared as the UNESCO Heritage Site which is a matter of pride for the district.