Ariyalur District is the youngest and most backward district in
. The district is bordered by the districts of Cuddalore
in the north, Perambalur
in the west, Thanjavur
in the south and Nagapattinam
in the east. It is considered to be the "Land of Fossils". Many prehistoric fossils are found in Ariyalur District. Recently, paleontologists have found a dinosaur's egg in Ariyalur. It has a population of about 1 million.