Thrissur ( Trichur / Trishur) (Malayalam: തൃശ്ശൂര്‍) is a revenue district of Kerala situated in the central part of that state. Spanning an area of about 3,032 km², Thrissur district is home to over 10% of Kerala’s population. Thrissur district was formed on July 1, 1949, with the headquarters at Thrissur City. Thrissur is known as the cultural capital of Kerala, and the land of Poorams. The district is famous for its ancient temples, churches, and mosques. Thrissur Pooram is the most colourful and spectacular temple festival in Kerala.

The name Thrissur is derived from 'Thiru-Shiva-Perur' (Malayalam / Tamil), which translates to "The city with the name of the Lord Siva". Thrissur was also known as "Vrishabhadripuram" and "Then Kailasam" (Kailasam of the south) in ancient days.^{[citation needed]} Another interpretation is 'Tri-shiva-peroor' or the big land with three Shiva temples, which refers to the three places where Lord Shiva resides - namely Vadakkunnathan temple, Asokeswaram Siva temple and Irattachira Siva temple.

Thrissur  pronunciation (help·info) (Malayalam: തൃശൂര്‍), originally Thrisivaperoor and previously known by its anglicized form as Trichur, is the fifth largest city, the third largest urban agglomeration in Kerala (Pop. 1,854,783) and the 20th largest in India. It is also the headquarters of the Thrissur District. Thrissur city is built around a 65-acre (26 ha) hillock called the Thekkinkadu Maidan which seats the Vadakkumnathan temple. Thrissur was once the capital of the Kingdom of Cochin. It is located 300 kilometres (186 mi) towards north-west of the state capital Thiruvananthapuram.

Thrissur is also known as the Cultural Capital of Kerala because of its cultural, spiritual and religious leanings throughout history. It houses the Kerala Sangeetha Nadaka Academy, Kerala Lalita Kala Akademi and Kerala Sahitya Academy. The city hosts the Thrissur Pooram festival, the most colourful and spectacular temple festival in Kerala. The festival is held at the Thekkinkadu Maidan in April or May. Thrissur has a large number of well-known temples including the Thiruvambadi Sri Krishna Temple, Vadakkumnathan temple and Paramekkavu temple, as well as two famous churches, the Our Lady of Lourdes Metropolitan Cathedral and the Basilica of Our Lady of Dolours.