Thalassery was formerly under Cannanore Sub Division. After the communist Rebellion of April 1948, the Sub Division was split as Cannanore and Cannanore Special Sub Division. In 1950, the Headquarter of DySP, Cannanore was shifted to Thalassery. In 19/7/1961 Thalassery Sub Division was formed by renaming Cannanore sub division as per GO(Rt.) No.928/70/Home, dated 27/5/1970. In 2005 a new police Sub division was formed at Iritty and Panoor. Panoor Sub Division was abolished and formed at Iritty, Peravoor Mattannur Circle were attached with Iritty Sub Division and Panoor and Kuthuparamba Circle with Thalasserry Sub Division. At present this sub division consists of 8 Police Stations. Thalasserry, Dharmamdam , New Mahe,Pinarayi, Chokly,   Kadiroor,Thalassery costal and Control room comes under Thalassery sub-division.
Almost all Police Stations in this Sub Division are politically sensitive and certain areas in all circles are communally sensitive. This Sub Division was having past history of Naxalite attack on November 22, 1968 which was one of its kinds of first incidents in Kerala. Thalasserry and surrounding areas had witnessed communal riot in 1971 and all circle limits political clashes between CPI(M) and BJP/RSS including murder, attempt to murder, arson etc using deadly weapons and explosive substance since 1978.
Police Stations in Thalassery Sub Division
Thalassery Sub Division
New Mahe PS
Traffic Unit Thalassery
Thalassery costal PS