Tamil Nadu had a bicameral legislature until 1986, when it was replaced with a unicameral legislature, like most other states in India. The term length of the government is 5 years, as is elsewhere in India. The present government run by the DMK led alliance came to power in 2006 and comprises a council of 29 ministers, chaired by the Chief Minister. Dr.M.Karunanidhi. Tamil Nadu legislative assembly is chaired by the speaker Mr. R Avudaiappan and is housed at the Omandurar Government Estate in Chennai. The state had come under the President's rule on four occasions – first from 1976 to 1977, next for a short period in 1980, then from 1988 to 1989 and the latest in 1991.
Tamil Nadu has 10 City Corporations: Chennai, Coimbatore, Madurai, Tiruchirapalli, Salem, Tirunelveli, Erode, Tirupur, Vellore and Thoothukudi. There is a plan to upgrade Nagercoil and Thanjavur as City Corporations. The Corporation of Chennai, established in 1688, is the oldest Municipal Corporation not only in India but also in any commonwealth nations outside United Kingdom.
Tamil Nadu has been a pioneering state of E-Governance initiatives in India. A large part of the government records like land ownership records are digitised and all major offices of the state government like Urban Local Bodies — all the Corporations and Municipal Office activities — revenue collection, land registration offices, and transport offices have been computerised. Tamil Nadu is one of the states where law and order has been maintained largely successfully. The Tamil Nadu Police Force is over 140 years old. It is the fifth largest state police force in India and has the largest strength of women police personnel in the country. As of 2003, the state had a total police population ratio of 1:668, higher than the national average of 1:717.The current Director General of Police (law and order) of Tamil Nadu is Latika Charan.