Chennai district

Chennai district, also known as Madras district, It is one of the 38 districts in the state of Tamil Nadu, India. It is the smallest and the most densely populated district in the state. The district is coterminous with the city of Chennai, which is administered by the Greater Chennai Corporation It is surrounded by Tiruvallur district in the north and the west, Kanchipuram district in the south-west, Chenglpattu district in the south, and the Bay of Bengal in the east.

Chennai district was originally created as Madras district by the British East India Company in 1798 for the revenue administration of the presidency town of Madras. The district has been existence since then barring a short period between 1860 and 1870 when the Madras district was abolished and its area administered as part of Chingleput district. Chennai district comprises only a single municipal body - the Greater Chennai Corporation and for most its history, it has been the smallest, most populous, most urbanised as well as the most densely populated district in the state.

As of 2011, the district had a population of 67,48,026 with a sex ratio of 989 females for every 1,000 males. In 2018, the district's limits were expanded, aligning with that of the newly expanded Greater Chennai Corporation, which had annexed adjacent municipalities. This resulted in the area being increased from 175 square kilometres (68 mi) to 426 square kilometres (164 mi). The district is divided into three revenue divisions and sixteen taluks.