Trincomalee (English: /ˌtrɪŋkoʊməˈliː/; Tamil: திருக்கோணமலை, romanized: Tirukkōṇamalai, IPA: [t̪iɾukːoːɳɐmɐlɛi̯]; Sinhala: ත්‍රිකුණාමළය, romanized: Trikuṇāmaḷaya, IPA: [t̪rikunaːmələjə]), historically known as Gokanna and Gokarna, is the administrative headquarters of the Trincomalee District and major resort port city of Eastern Province, Sri Lanka. Located on the east coast of the island overlooking the Trincomalee Harbour, Trincomalee has been one of the main centres of Sri Lankan Tamil speaking culture on the island for nearly a millennium. With a population of 99,135, the city is built on a peninsula of the same name, which divides its inner and outer harbours. It is home to the famous Koneswaram temple from where it developed and earned its historic Tamil name Thirukonamalai. The town is home to other historical monuments such as the Bhadrakali Amman Temple, Trincomalee, the Trincomalee Hindu Cultural Hall and, opened in 1897, the Trincomalee Hindu College. Trincomalee is also the site of the Trincomalee railway station and an ancient ferry service to Jaffna and the south side of the harbour at Muttur.

Trincomalee was made into a fortified port town following the Portuguese conquest of the Jaffna kingdom, changing hands between the Danish in 1620, the Dutch, the French following a battle of the American Revolutionary War and the British in 1795, being absorbed into the British Ceylon state in 1815. The city's architecture shows some of the best examples of interaction between native and European styles. Attacked by the Japanese as part of the Indian Ocean raid during World War II in 1942, the city and district were affected after Sri Lanka gained independence in 1948, when the political relationship between Tamil and Sinhalese people deteriorated, erupting into civil war. It is home to major naval and air force bases at the Trincomalee Garrison. The city also has the largest Dutch fort on the island.

The Trincomalee Bay, bridged by the Mahavilli Ganga River to the south, the historical "Gokarna" in Sanskrit, means "Cow's Ear", akin to other sites of Siva worship across the Indian subcontinent. Uniquely, Trincomalee is a Pancha Ishwaram, a Paadal Petra Sthalam, a Maha Shakta pitha and Murugan Tiruppadai of Sri Lanka; its sacred status to the Hindus has led to it being declared "Dakshina-Then Kailasam" or "Mount Kailash of the South" and the "Rome of the Pagans of the Orient". The harbour is renowned for its large size and security; unlike any other in the Indian Ocean, it is accessible in all weathers to all craft. It has been described as the "finest harbour in the world" and by the British, "the most valuable colonial possession on the globe, as giving to our Indian Empire a security which it had not enjoyed from elsewhere".^{[citation needed]}

The city has developed from a village settlement on the promontory dedicated to the Hindu shrine. The origin of the term Ko, Kone and Konatha lies in the Old Tamil word for the terms "Lord", "King" or "Chief", which allude to the deity that presides here; this term appears in several Tamil Brahmi inscriptions of the 6th century BCE — 2nd century CE. Trincomalee, the coastal peninsula town where Koneswaram is located is an anglicized form of the old Tamil word "Thiru-kona-malai" (Tamil: திருக்கோணமலை), meaning "Lord of the Sacred Hill", its earliest reference in this form found in the Tevaram of the 7th century by Sambandhar. Thiru is a generally used epithet denoting a "sacred" temple site while Malai means mountain or hill; Middle Tamil manuscripts and inscriptions mention the monumental compound shrine as the Thirukonamalai Konesar Kovil. Kona (Tamil: கோண) has other meanings in Old Tamil such as peak, while another origin for the term Koneswaram could come from the Tamil term Kuna (East). Therefore, other translators suggest definitions of Trincomalee such as "sacred angular/peaked hill", "sacred eastern hill" or "three peaked hill". The temple was constructed atop Swami Rock, also called Swami Malai or Kona-ma-malai, a cliff on the peninsula that drops 400 feet (120 metres) directly into the sea.

The Trincomalee Harbour, a circular natural harbour which the temple crowns towards the north, is referred to as Ko-Kannam or "Lord's Cheek", alluding to the cheek shape of Shiva's bull Nandi. The Sanskrit equivalent of the port town's harbour bay is Go-Karna, meaning "Cow's Ear" or Gokarna Pattana and the deity's name Gokarneswara or Go—Natha in Sanskrit. Pathmanathan offers the etymological link Thiru-Gokarna-Malai or Thiru-Gona-Malai based on this connection.

The ethnographer Megasthenes writing in his Indica from 350 — 290 BCE, describes the island as being divided by a long river, productive of a large number of gold and pearls in one half and that the inhabitants of this country are called Paleogoni, meaning Old Goni in Tamil and Greek, who Pliny adds worshipped Hercules and Dionysus (Bacchus) like the Pandyans of Tamilakam. The Vayu Purana, written in 300 CE specifically mentions the tallest mountain peak of the great gold and silver rich mountain range Malaya on the island, and that "to the east of this island at the shore of the sea lies a great Siva temple in a holy place called Gokarna." The bay is also referred to as Gokaranna according to a Sanskrit inscription in Grantha script excavated on a doorjamb at the Hindu temple dated to Tamil New Years Day 1223 CE. Gokarna is also a place name in Karnataka, India, Kalinga, Tamil Nadu and Nepal all associated with ancient Shiva temples. The associated Bhadrakali Amman Temple of Trincomalee, significantly expanded by Rajendra Chola I, stands on Konesar Road before the entrance to Swami Rock.

Heralded as "Dakshina Kailasam"/"Then Kailasam" (Kailaas of the South) because it lies on exactly the same longitude as the Tibetan mountain Mount Kailash (the primary abode of Shiva), Trincomalee's traditional history and legends were compiled into the Sanskrit treatises Dakshina Kailasa Puranam — Sthala Puranam of Koneswaram, written in 1380 by Jeyaveera Cinkaiariyan, and the Dakshina Kailasa Manmiam — three chapters of the Skanda Puranam of unknown antiquity — manuscripts of which have been discovered and dated from the 5th — 7th century. It was in the Puranas that the shrine first found reference as Koneiswara Parwatia, motivating Kullakottan Chola who learnt of its sanctity to sail to Trincomalee and develop the three Hindu temples of the Koneswaram compound. The compiler of the Yoga Sutras, Patañjali's place of birth at the temple corroborates Tirumular's Tirumandhiram, which describes him as hailing from Then Kailasam and his self description as a "Gonardiya" from Gonarda, "a country in the southern and eastern division" of the Indian continent. Both men were ardent disciples of Nandi. The Konesar Kalvettu uses the term Tiri Kayilai, meaning "three Kailasams", Tiri Kutam and Tiri Konam for Trincomalee, in a number of places, referring to the three pagodas on the promontory of Trincomalee.

As per another legend, Vayu Bhaghvan and Adiseshan had a dispute to find out who is superior, to prove the superiority adiseshan encircled the Kailasam, Vayu tried to remove this encircle by creating santamarutham (Twister). Due to the santamarutham, eight (8) kodumudigal (parts) fell from kailasam into 8 different places: are Thirugonamalai (Trincomalee), Thirukalahasti, Thiruchiramalai, Thiruenkoimalai, Rajathagiri, Neerthagiri, Ratnagiri, and Suwethagiri Thirupangeeli.