Map - Tiruchirappalli

Tiruchirappalli (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 km south of Chennai and 374 km north of Kanyakumari, Tiruchirappalli sits almost at the geographic centre of Tamil Nadu state. The Cauvery Delta begins 16 km 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 km2 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.

Historically, Tiruchirappalli was commonly referred to in English as "Trichinopoly". The shortened forms "Trichy" or "Tiruchi" are used in everyday speech and the full name Tiruchirapalli appears in official use by government and quasi-government offices but seldom used by the general public.

According to the late scholar C. P. Brown, Tiruchirappalli might be a derivative of the word Chiruta-palli (lit. "little town"). Orientalists Henry Yule and Arthur Coke Burnell have speculated that the name may derive from a rock inscription carved in the 16th century in which Tiruchirappalli is written as Tiru-ssila-palli, meaning "holy-rock-town" in Tamil. Other scholars have suggested that the name Tiruchirappalli is a rewording of Tiru-chinna-palli, meaning "holy little town". The Madras Glossary gives the root as Tiruććināppalli or the "holy (tiru) village (palli) of the shina (Cissampelos pareira) plant".

According to Hindu mythology, Tiruchirappalli derives its name from the three-headed demon Trishira, who meditated on the Hindu god Shiva near the present-day city to obtain favours from the god. An alternative derivation, albeit not universally accepted, is that the source of the city's name is the Sanskrit word "Trishirapuram"—Trishira, meaning "three-headed", and palli or puram meaning "city".