Tiruchirappalli also called Tiruchi or Trichy, is a city in the Indian state of Tamil Nadu and the administrative headquarters of Tiruchirappalli District. It is the fourth largest municipal corporation and the fourth largest urban agglomeration in the state. Located 322 kilometres (200 mi) south of Chennai and 379 kilometres (235 mi) north of Kanyakumari, Tiruchirappalli sits almost at the geographic centre of the state. The Kaveri Delta begins 16 kilometres (9.9 mi) west of the city as the Kaveri river splits into two, forming the island of Srirangam, now incorporated into Tiruchirappalli City Municipal Corporation. Occupying 167.23 square kilometres (64.57 sq mi), the city was home to 916,857 people as of 2011.

Tiruchirappalli is one of the oldest inhabited cities in Tamil Nadu; its earliest settlements date back to the second millennium BC.Uraiyur, the capital of the Early Cholas for 600 years from the 3rd century BC onwards,is a suburb of present-day Tiruchirappalli.The city is referred to as Orthoura by the historian Ptolemy in his 2nd-century work Geography.The world’s oldest surviving dam, the Kallanai (Lower Anaicut) about 18 kilometres (11 mi) from Uraiyur,was built across the Kaveri River by Karikala Chola in the 2nd century AD.The medieval history of Tiruchirappalli begins with the reign of the Pallava king Mahendravarman I, who ruled over South India in the 6th century AD and constructed the rock-cut cave-temples within the Rockfort.

The Carnatic kingdom was annexed by the British in July 1801 as a consequence of the discovery of collusion between Tipu Sultan—an enemy of the British—and Umdat Ul-Umra, son of Wallajah and the Nawab at the time, during the Fourth Anglo-Mysore War.Trichinopoly was incorporated into the Madras Presidency the same year, and the district of Trichinopoly was formed, with the city of Trichinopoly as its capital.

During British rule, Tiruchirappalli was known for its tanneries, cigar-manufacturing units and oil presses.At its peak, more than 12 million cigars were manufactured and exported annually.Tanned hides and skins from Tiruchirappalli were exported to the United Kingdom.The city has a number of retail and wholesale markets, the most prominent among them being the Gandhi Market, which also serves people from other parts of the district.Other notable markets in the city are the flower bazaar in Srirangam and the mango market at Mambazha Salai. The suburb of Manachanallur is known for its rice mills, where polished Ponni rice is produced

A resident of Tiruchirappalli is generally referred to as a Tiruchiite. Situated at the edge of the Kaveri Delta, the culture of Tiruchirappalli is predominantly Brahminical, prevalent elsewhere in the delta.With a substantial population of students and migrant industrial workers from different parts of India, Tiruchirappalli has a more cosmopolitan outlook than the surrounding countryside.The main festival celebrated in Tiruchirappalli is Pongal, a regional harvest festival celebrated during January. As part of the Pongal celebrations, Jallikattu, a bull-taming village sport played on the last day of the festival,is occasionally held on the outskirts of the city. Aadi Perukku, Samayapuram flower festival, Vaikunta Ekadasi,Srirangam car festival,and the Teppakulam float festival are some of the prominent festivals that are held locally.Bakrid and Eid al-Fitr are also widely celebrated, owing to the substantial number of Muslims in the city.Nationwide festivals such as the Gregorian New Year,Christmas, Deepavali and Holi are also celebrated in Tiruchirappalli.

Tiruchirappalli has been recognised in India as an important educational centre since the time of British rule. St. Joseph’s College, which opened in Nagapattinam in 1846 and transferred to Tiruchirappalli in 1883, is one of the oldest educational institutions in South India.The Society for the Propagation of the Gospel (SPG) college, established in 1883, is a premium missionary institution in the city.