Tamil Nadu (; Tamil: [ˈtamiɻ ˈnaːɽɯ] (listen), abbr. TN) is a state in southern India. It is the tenth largest Indian state by area and the sixth largest by population. Its capital and largest city is Chennai. Tamil Nadu is the home of the Tamil people, whose Tamil language—one of the longest surviving classical languages in the world—is widely spoken in the state and serves as its official language. The state lies in the southernmost part of the Indian peninsula, and is bordered by the Indian union territory of Puducherry and the states of Kerala, Karnataka, and Andhra Pradesh, as well as an international maritime border with Sri Lanka. It is bounded by the Western Ghats in the west, the Eastern Ghats in the north, the Bay of Bengal in the east, the Gulf of Mannar and Palk Strait to the south-east, and the Indian Ocean in the south. The at-large Tamilakam region that has been inhabited by Tamils was under several regimes, such as the Sangam era rulers of the Chera, Chola, and Pandya clans, the Pallava dynasty, and the later Vijayanagara Empire, all of which shaped the state's cuisine, culture, and architecture. After the fall of the Kingdom of Mysore, the British colonised the region and administered it as part of the Madras Presidency, headquartered at the city of Madras, now known as Chennai. After India's Independence in 1947, the Madras State came into existence, whose borders were linguistically redrawn by the States Reorganisation Act, 1956, losing territory to Kerala, Karnataka and Andhra Pradesh. The state was renamed as Tamil Nadu in 1969. It is home to a number of historic buildings, multi-religious pilgrimage sites, hill stations and three World Heritage Sites.The economy of Tamil Nadu is the second-largest in India, with a gross state domestic product (GSDP) of ₹24.85 lakh crore (US$310 billion) and has the country's 11th-highest GSDP per capita of ₹225,106 (US$2,800). It ranks 11th among all Indian states in human development index. Tamil Nadu is the most urbanised state in India, and one of the most industrialised states; the manufacturing sector accounts for more than one-third of the state's GDP. Its tourism industry is the largest among the Indian states. The Tamil film industry plays an influential role in the state's popular culture.

Tiruchirappalli (pronunciation ) (formerly Trichinopoly in English), also called Tiruchi or Trichy, is a major tier II city in the Indian state of Tamil Nadu and the administrative headquarters of Tiruchirappalli district. The city is credited with being the best livable city and the cleanest city of Tamil Nadu, as well as the fifth safest city for women in India. It is the fourth largest city as well as the fourth largest urban agglomeration in the state. Located 322 kilometres (200 mi) south of Chennai and 374 kilometres (232 mi) north of Kanyakumari, Tiruchirappalli sits almost at the geographic centre of Tamil Nadu state. The Cauvery Delta begins 16 kilometres (9.9 mi) west of the city where the Kaveri river splits into two, forming the island of Srirangam which is now incorporated into the Tiruchirappalli City Municipal Corporation. The city occupies an area of 167.23 square kilometres (64.57 sq mi) and had a population of 916,857 in 2011.Tiruchirappalli's recorded history begins in the 3rd century BC, when it was under the rule of the Cholas. The city has also been ruled by the Pallavas, Pandyas, Vijayanagar Empire, Nayak Dynasty, the Carnatic state and the British. The most prominent historical monuments in Tiruchirappalli include the Rockfort at Teppakulam, the Ranganathaswamy temple at Srirangam dedicated to the reclining form of Hindu God Vishnu, and is also the largest functioning temple in the world, and the Jambukeswarar temple at Thiruvanaikaval, which is also the largest temple for the Hindu God Shiva in the world. The archaeologically important town of Uraiyur, capital of the Early Cholas, is now a neighbourhood in Tiruchirappalli. The city played a critical role in the Carnatic Wars (1746–1763) between the British and the French East India companies. The city is an important educational centre in the state of Tamil Nadu, and houses nationally recognised institutions such as National Institutes of Technology (NIT), Indian Institutes of Management (IIM) National Law Universities (NLU), and Indian Institutes of Information Technology (IIIT) Srirangam. Industrial units such as Bharat Heavy Electricals Limited (BHEL), Golden Rock Railway Workshop, Ordnance Factory Tiruchirappalli (OFT) and High Energy Projectile Factory (HEPF) have their factories in the city. The presence of a large number of energy equipment manufacturing units in and around the city has earned it the title of "Energy Equipment and Fabrication Capital of India". Tiruchirappalli is internationally known for a brand of cheroot known as the Trichinopoly cigar, which was exported in large quantities to the United Kingdom during the 19th century. A major road and railway hub in the state, the city is served by the Tiruchirappalli International Airport (TRZ) which operates flights to the Middle East and Southeast Asia.