The word Thrissur is derived and anglicized form of the Malayalam word "THRISSIVAPERUR". During the ancient period, Thrissur played a significant role in the political history of India. This is linked with that of the Cheras of the Sangam age, who ruled over vast portions of Kerala with their capital at Vanchi. The whole of the present Thrissur District was included in the early Chera Empire.
The District can claim to have played a significant part in fostering the trade relations between Kerala and the outside world in the ancient and medieval period. It can also claim to have played an important part in fostering cultural relations and in laying the foundation of a cosmopolitan and compose culture in this part of the country. Kodungalloor which had the unique distinction of being the "Premium Emporium India", also belongs to the signal honour of having first given shelter to all the three communities which have contributed to the prosperity of Malabar'. These three communities are the Christians, the Jews and the Muslims.
In 1790 Raja Rama Varma (1790-1805) popularly known as Saktan Thampuran ascended the throne of Cochin. With the accession of this ruler the English or modern period in the history of Cochin and of the District began. As his very name suggests, this prince was a strong ruler and his reign was characterized by firm and vigorous administration. Saktan Thampuran was mainly responsible for the destruction of the power of the feudal chieftains and increase of royal power. The anti-feudal measures of Saktan Thampuran coupled with the several administrative reforms introduced by him marked the end of the medieval period in the history of Cochin and ushered in the modern epoch of progress.
Thrissur District was the venue for the National Movement with regard to the Independence Struggle of India. In the Civil Disobedience Movement of 1921, several persons in Thrissur Town and other places in the District took active part and courted arrest. Thrissur District can claim the honour of having been in the forefront of the country-wide movement for temple entry and abolition of untouchability. The famous Guruvayur Satyagraha is a memorable episode in the history of the national movement.
The Quit India movement of 1942 has its echoes in the District. After the release of the leaders from jail in 1943, the Cochin State Praja Mandal pursued its organizational activities more vigorously.
The first step towards the achievement of the goal of Aikyakerala was taken with the integration of Travancore Cochin States in July 1949. With the linguistic reorganization of States in India, in November 1956 the Kerala State came into existence.
The history of Thrissur District Police Starts after the formation of Aikyakeralam in 1949. Sri. A R Mannadiyar was the first Superintendent of Police of Thrissur District. He held the post with effect from 01.07.1949 to 19.03.1951. Thereafter 44 other Police Officers held the post of Superintendent of Police Thrissur.
Thrissur Police District was bifurcated as Thrissur Rural and Thrissur City with effect from 01.03.2011. Twelve Police Stations were come under the jurisdiction of Thrissur City and 26 Police Stations were come under Thrissur Rural Police District.
The long coastal belt on the western side of the District which is approximately 60 kilometers is very sensitive, politically and communally. There are many communal and political hot-spots within Kodungallur, Mathilakam, Valappad, Vatanappilly, Chavakkad, Kunnamkulam and Vadakkekad Police Station limits along the coast.