The District has Vellar River in the North and it has well marked natural divisions.
The ground water resource through tube wells and wells are the most important source of irrigation. The major crops grown in the district are paddy, groundnut, sugarcane, millets and Cashew. Perambalur accounts for about 24% of the small onion produced in Tamil Nadu and holds the first place in its production in the State.
As per 2011 Census, the total Population of Perambalur District is 5,65,223. The density of population in the district is 321 per Sq.Km
Composite Trichirappalli District was trifurcated as per G.O.Ms.No.913 Revenue (Y3) Department Dated: 30.09.1995 and New Perambalur District with headquarters of Perambalur was formed. Composite Perambalur District came in to existence after trifurcation of Tiruchirappalli district with effect from 30.09.1995 as per G.O MS.No 913 Revenue / Y3 dated 30.09.1995. The District first came into existence on 01-01-1995.
In the Government Orders G.O (Ms)No. 656, Revenue, Dated. 29.12.2000 and G.O (Ms)No. 657, Revenue, Dated. 29.12.2000 , the Government ordered Perambalur District to be bifurcated into two Districts , Perambalur District with headquarters at Perambalur and Ariyalur District with headquarters at Ariyalur. Later the Government in G.O.Ms.NO. 656 Revenue Department Dated:29.12.200 and G.O.Ms.No.657 Revenue Department Dated: 29.12.2000 have ordered bifurcating the Perambalur District into two Districts as Perambalur with headquarters at Perambalur and Ariyalur with headquarters at Ariyalur.
Subsequently, in the Government orders G.O (Ms)No. 167, Revenue, Dated. 19.4.2002, and G.O (Ms)No. 168, Revenue, Dated. 19.4.2002 , the Government ordered that the above two districts be merged into one as Perambalur District with headquarters at Perambalur. – Subsequently the Government in G.O.Ms.No.167 Revenue Department Dated: 19.04.2002 and G.O.Ms.No.168 Revenue Department Dated: 19.04.2002 have ordered the Ariyalur District be merged with Perambalur District with headquarters at Perambalur. Again the combined Perambalur district came into existence on 19.04.2002.
Later, vide the Government Order G.O (Ms) NO. 683 Dated. 19.11.2007, Government again ordered that Perambalur District be reorganised and bifurcated into two districts as Perambalur and Ariyalur and Perambalur District with headquarters at Perambalur & Ariyalur district with headquarters at Ariyalur.