North latitude between 12°15' and 13°15', east longitude between 79°15' and 80°20'
The district is surrounded by Kancheepuram district in the South, Vellore district in the west. Bay of Bengal in the East and Andhra Pradesh State in the North. The district spreads over an area of about 3422 Sq.kms.
The coastal region of the district is mostly flat and dreary; but in the other parts it is undulating and even hilly in some places.
The northern taluks of the district like Ponneri, Uttukkottai, Gummidipundi etc. do not have much to offer from the scenic point of view. In the Tiruttani taluk, a number of hillocks are found scattered.
The soil of the district is mostly sandy, mixed with soda or other alkali or stony. Rocks found in and near the surface are in detached masses. Hence, the soil can't be termed as very fertile. The soil found nearer the sea coast is of the inferior erinaceous type which is most suited for raising casuarinas plants. No mineral of any importance is available in the district.
There are not many hills of any considerable height in this district. A few conical hills or ridges of small elevation exist like the St. Thomas Mount. Certain hillocks are found in Tiruttani. Most of the hills and hillocks are rocky and no verdant vegetation is seen in the slopes of these hills. The area under forests in this district is quite meager.
The total geographical area of the district is 3,42,243 hectares of which not sown area constitute 35% whereas forest covers 5.8% of the total area. The nine-fold clarification of the land are pattern is given below.
|Details||Area Ha.||% Share to Total Area|
|Barren and Unculturable Lands||13727||4.01|
|Land put to Non - Agricultural Uses||98729||28.85|
|Permanent Pasture and other Grazing Lands||8142||2.38|
|Miscellaneous Tree Crops and Groves not included in the Net Area Sown||8280||2.42|
|Other Fallow Lands||51813||15.14|
|Net Area Sown||120169||35.11|
The average normal rainfall of the District is 1104 mm. Out of which 52% has been received during North East Monsoon period and 41% has been received during South West Monsoon period.