The town of Poonamallee is situated at a distance of 23 kilometres from Fort St George and 17 kilometres from Sriperumbudur on the Chennai-Bangalore highway. It is located at the end of the Mount-Poonamallee Road and Poonamalle High Road, 11 kilometres from Guindy and 13 kilometres from Chennai Mofussil Bus Terminus on the Chennai bypass. The nearest railway station is at Avadi & Thiruninravur which is nine kilometres away. It is also an important halting point for buses starting from Chennai Mofussil Bus Terminus and going towards Tirupati, Kanchipuram, Vellore etc.
The name "Poonamallee" might have been derived from "Poovirundavalli", meaning "the place where jasmine is cultivated". In Sanskrit, the place is called Pushpakavalli. Pushpam' means flower and Valli denotes Goddess. There is a legend that Goddess Laxmi rose from jasmine flower and gave darashan to Thirukatchi Nambi Alwar. It is also said the Alwar worshipped God Varadaraja, deity at Kanchi with the jasmine flowers plucked from here. This place is also called "Lakshmipuram' and Ulagu Vuyya Konda Cholapuram.
Poonamallee is believed to be the birth place of Thirukatchi Nambi Alwar, a staunch devotee of Varadaraja Perumal. There is an ancient temple for lord Varadaraja Perumal with his consort, Pushpakavalli Thayar. It is also known as Arulaperumal. There is also another temple, a medium sized one, here for Lord Vaidyanathaswami with His Consort Thaiyal Nayagi. He is known as Theera Vinai Theertha Perumal. Poonamallee is famous for its Siva temple which has three inscriptions dating to the 18th century AD. there are three Old Traditional C churches and a mosque was built and completed by Rustom, son of Dhulfiquer of Astrabad, a servant of Nawab Jumlat-ul-mulk. A Persian inscription dated 1653 A.D., found in the mosque reveals this information." There is also a Muhammedan fort nearby. There is also old cemetery in Poonamallee, which is the resting place of many British missionaries. The bus stop next to the cemetery says Kallarai, which is the Tamil word for cemetery.
According to 2011 census, Poonamallee had a population of 57,224 with a sex-ratio of 999 females for every 1,000 males, much above the national average of 929. A total of 6,496 were under the age of six, constituting 3,313 males and 3,183 females. Scheduled Castes and Scheduled Tribes accounted for 15.24% and .1% of the population respectively. The average literacy of the town was 78.88%, compared to the national average of 72.99%. The town had a total of 14668 households. There were a total of 22,411 workers, comprising 133 cultivators, 226 main agricultural labourers, 576 in house hold industries, 18,084 other workers, 3,392 marginal workers, 29 marginal cultivators, 35 marginal agricultural labourers, 128 marginal workers in household industries and 3,200 other marginal workers. As per the religious census of 2011, Poonamallee had 75.88% Hindus, 13.34% Muslims, 9.03% Christians, 0.02% Sikhs, 0.02% Buddhists, 0.29% Jains, 1.41% following other religions and 0.01% following no religion or did not indicate any religious preference.
Poonamallee is governed by Municipality of Poonamallee, coming under the Thiruvallur district. Poonamallee Municipality is situated in the West Chennai of Tamil Nadu in Thiruvallur District. This town is surrounded with infrastructural facilities and it is near to visit Chennai Metropolitan Bus Terminal (CMBT).The town's traffic is managed by the Chennai Traffic Police (CTP). The town's police comes directly under Chennai Metropolitan Police department. The town elects 1 MLA to the state legislature and comes under Thiruvallur Parliamentary constituency. The town is famous for its 8 courts including the special courts for bomb blasts. It has gained importance since this court system dealt with the assassination of former Indian Prime Minister Rajiv Gandhi.
RTO: Poonamalee comes under RTO-POONAMALEE(TN-12). It is one of the largest RTO in Tamil Nadu in terms of vehicle registered. Previously it was under Tiruvallur RTO(TN20Y).
Poonamallee assembly constituency is part of Thiruvallur (Lok Sabha constituency). The Current MLA For Poonamallee Constituency is Mr. Elumalai from (2016 May) to as on. Thee MP for Thiruvallur District is Dr.P.Venugopal as on (2014 MAY) The Current MLA For Poonamallee Constituency is Elumalai as on (2016 May)
Some of the popular schools in Poonamallee areArignar Anna Government Higher Secondary School Which was started in 1902.This was the Largest Boys school in terms of students until 2004, then has been converted into Co-education School., Poonamallee
St.John's International Residential School (SJIRS).
Jeya Jeya Sankara International school, Poonamallee
Sundar Matriculation Higher Secondary School, Poonamallee
St.Joseph's Matriculation Higher Secondary School, Poonamallee
Christ Matriculation Higher Secondary School, Poonamallee
Kalashetra Matriculation Higher Secondary School, Poonamallee
Holy Crescent Matriculation Higher Secondary School, Poonamallee
Arignar Anna Govt Higher Secondary School, Poonamallee
New St.Joseph's Matriculation Higher Secondary School, Poonamallee
Sathya Matriculation School, Poonamallee
Sarojini Varadappan Girls Higher Secondary School, Poonamallee
Joy Bell Matriculation School, Poonamallee
Daniel Matriculation School, Poonamallee
Apollo Vidyashram, Poonamallee
Thiruvalluvar Middle School, Nambi Nagar, Poonamallee
Sree Sastha Institute of Engineering and Technology
Jaya College of Engineering and Technology
Panimalar Engineering College
Sastha Engineering College
SKR Engineering College
Apollo Arts & Science College
Apollo Engineering College
Sri Muthukumaran Institute of Technology
Be Well Hospital
Aravind Eye Hospital
Sundar Theatre (old), Gokulam Pavilion (New)