Chennai district
Coordinates: 13°5′2″N 80°16′12″E / 13.08389°N 80.27000°E
Chennai district (Tamil: சென்னை மாவட்டம்), also and formerly known as Madras district or "Madarasapattinam", is a district in the state of Tamil Nadu, in India. It is the smallest of all the districts in the state, but has the highest human density. The district is a city district which means that it does not have a district headquarters. Most of the city region of Chennai comes under this district. As of 2011, the district had a population of 4,646,732 with a sex-ratio of 989 females for every 1,000 males.
Chennai district covers an area of 178.2 km2 located on the Eastern Coastal Plains of India. It is situated on the northeastern corner of Tamil Nadu along the Coramandel coast, a region bounded by the Bay of Bengal and is surrounded inland by the districts of Tiruvallur and Kanchipuram. It lies between 12°59' and 13°9' of the northern latitude and 80°12' and 80°19' of the eastern longitude at an average altitude of 6 metres above sea level on a 'sandy shelving breaker swept' beach. Terrain slope varies from 1:5000 to 1:10,000. The terrain is very flat with contours ranging from 2 m to 10 m above mean sea level with a few isolated hillocks in the southwest beyond the district limits at St. Thomas Mount, Pallavaram and Tambaram. The district runs inland in a rugged semi-circular fashion and its coastline is about 25.60 km (2.5% of the total coastline of Tamil Nadu). Because of its strategic location and economic importance, it is referred to as the "Gateway of South India." The drainage system includes two rivers, namely, Cooum (flowing in the northern part) and Adyar (flowing in the southern part), a canal (the Buckingham), and a stream (the Otteri Nullah) slicing the district into several islands.
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