Before 1947
During the British Raj, the Madras Presidency was made up of 26 districts, 12 of which were part of the boundaries of the present-day Tamil Nadu, namely, Chingleput, Coimbatore, Nilgiris, North Arcot, Madras, Madura, Ramnad, Salem, South Arcot, Tanjore, Tinnevely
1947–56
AfterIndependence the Madras Presidency became the Madras Province of the Dominion of India.
Pudukottai acceded to the Indian Union on 4 March 1948 and was made as a part of the Trichinopoly district.
When the new Constitution of India came into force on 26 January 1950, the Madras Province became the Madras State of the Republic of India.
The Madras State included most of the present-day Tamil Nadu, Coastal Andhra and Rayalaseema regions of the present-day Andhra Pradesh, the Malabar region of the present-day Kerala, Bellary and South Canara districts of the present-day Karnataka.
The Coastal Andhra and Rayalaseema regions were separated to form the new Andhra State in 1953.
As a result of the re-organization of states in 1956, South Canara and Bellary districts were merged with Mysore State, which became Karnataka and the Malabar district was added to the State of Travancore-Cochin to form Kerala. The Tamil speaking regions of Kanyakumari, which were earlier part of Travancore-Cochin, were merged to the Madras State.[6] After the reorganisation, the Madras state had 13 districts namely: Chingleput, Coimbatore, Kanyakumari, Madras, Madurai, Nilgiris, North Arcot, Ramanathapuram, Salem, South Arcot, Thanjavur, Tiruchirappalli and Tirunelveli.
1957–89
- In 1965, Dharmapuri district was bifurcated from the erstwhile Salem district comprising Dharmapuri, Harur, Hosur, and Krishnagiri taluks.
- In 1969, the Madras State was renamed as Tamil Nadu.
- In January 1974, Pudukkottai district was formed from the parts of Tiruchirappalli and Thanjavur districts comprising Kulathur, Thirumayam, Alangudi, and Aranthangi taluks.
- In August 1979, Erode district was bifurcated from the erstwhile Coimbatore district comprising Gobichettipalayam, and Erode taluks.
- In 1985, Sivaganga and Virudhunagar districts were formed from the erstwhile Ramanathapuram district. Sivaganga comprised Tirupattur, Karaikudi, Devakottai, Sivaganga, Manamadurai, and Ilayangudi taluks and Virudhunagar comprised Srivilliputhur, Virudhunagar, Tiruchuli, Aruppukottai, Sattur, and Rajapalayam taluks.
- In September 1985, Dindigul district was bifurcated from the erstwhile Madurai district comprising Dindigul, Palani, and Kodaikanal taluks.
- In October 1986, Thoothukudi district was split from the erstwhile Tirunelveli district comprising Thoothukudi, Ottapidaram, and Tiruvaikuntam taluks.
- In September 1989, Tiruvannamalai and Vellore districts were formed from the erstwhile North Arcot district. Tiruvannamalai district comprised Tiruvannamalai, Arni, Vandavasi, Cheyyar, Polur, and Chengam taluks
- Vellore district comprised Arakkonam, Arcot, Gudiyatham, Tirupattur, Vellore, Vaniyambadi, and Walajapet taluks.
1990–99
- On 18 October 1991, Nagapattinam was bifurcated from the erstwhile Thanjavur district comprising Tiruvarur, Mayiladuthurai, Manargudi, Needamangalam, Nagapattinam taluks, and Valangaiman from Kumbakonam taluk.[17]
- On 30 September 1993, Cuddalore and Viluppuram districts were formed from the erstwhile South Arcot district. Cuddalore district comprised Cuddalore, Chidambaram, and Vriddachalam taluks and Villupuram district comprised Kallakuruchi, Villupuram, Tirukkoyilur, and Tindivanam taluks.[18][19]
- On 30 September 1995, Karur and Perambalur districts were split from the erstwhile Tiruchirappalli district with Karur district comprising Karur, Kulithalai, and Manapparai taluksand Perambalur district comprising Perambalur, and Kunnam taluks.[20][21]
- On 25 July 1996, Theni district was bifurcated from the erstwhile Madurai district comprising Theni, Bodinayakanur, Periyakulam, Uthamapalayam and Andipatti taluks.[22]
- On 1 January 1997, Tiruvarur district was formed from the parts of erstwhile Nagapattinam and Thanjavur districts comprising Tiruvarur, Nannilam, Kudavasal, Needamangalam, Mannargudi, Thiruthiraipoondi taluks from Nagappatinam district and Valangaiman taluk from Thanjavur district.[23]
- On 1 January 1997, Namakkal district was bifurcated from the erstwhile Salem district comprising Namakkal, Tiruchengode, Rasipuram, and Paramathi-Velur taluks.[24]
- On 1 July 1997, Kanchipuram and Tiruvallur districts were split from the erstwhile Chengalpattu and Chennai districts with Kanchipuram district comprising Kanchipuram, Sriperumbudur, Uthiramerur, Chengalpattu, Tambaram, Tirukalukundram, Maduranthakam, and Cheyyur taluks and Tiruvallur district comprising Tiruvallur, Tiruttani, Ponneri, and Gummidipoondi taluks.[25]
2000–present
- On 9 February 2004, Krishnagiri district was bifurcated from the erstwhile Dharmapuri district comprising Krishnagiri, Hosur, Pochampalli, Uthangarai, and Denkanikottai taluks.[26]
- On 19 November 2007, Ariyalur district was bifurcated from the erstwhile Perambalur district comprising Ariyalur, Udayarpalayam, and Sendurai taluks.[27]
- On 24 October 2009, Tiruppur district was formed from the parts of Coimbatore and Erode districts comprising Tiruppur, Udumalpet taluks, parts of Palladam and Avinashi taluks of Coimbatore district, and Dharapuram, Kangeyam taluks and parts of Perundurai taluk of Erode district.[28]
- On 5 January 2018, the Chennai district was expanded by the addition of Madhavaram, Maduravoyal, Ambattur, Tiruvottriyur taluks, and parts of Ponneri taluk of Tiruvallur district along with Alandur, and Sholinganallur taluks of Kanchipuram district.[29]
- On 22 November 2019, Tenkasi district was bifurcated from the erstwhile Tirunelveli district comprising Tenkasi, Sengottai, Kadayanallur, Sivagiri, Veerakeralampudur, Sankarankovil, Thiruvenkatam, and Alangulam taluks.[30]
- On 26 November 2019, Kallakurichi district was bifurcated from the erstwhile Viluppuram district comprising Kallakurichi, Sankarapuram, Chinnasalem, Ulundurpet, Thirukovilur and Kalvarayanmalai taluks.[31]
- On 29 November 2019, Tirupattur and Ranipet districts were split from the erstwhile Vellore district with Tirupattur district comprising Tirupattur, Vaniyambadi, Natrampalli, and Ambur taluks and Ranipet district comprising Walajah, Arcot, Nemili, and Arakkonam taluks.[32]
- On 30 November 2019, Chengalpattu district was bifurcated from the erstwhile Kanchipuram district comprising Tirukalukundram, Chengalpattu, Madurantakam, Cheyyar, Tiruporur, Tambaram, Pallavaram, and Vandalur taluks.[33]
- On 24 March 2020, Mayiladuthurai district was formed from the erstwhile Nagapattinam district comprising Mayiladuthurai, Sirkazhi, Tharangambadi, and Kuthalam taluks.[
wiki/List_of_districts_of_Tamil_Nadu