Local stories date it back to the time of Sri Nityananda Prabhu. It is said that he once arrive to this place in a boat of hay ('Khar' in Bengali) and hence the name Khardaha. "Daha" means water bodies. It was full of water bodies at that time as it was for the entire southern part of Bengal.
The western part of Khardaha is a much older settlement. The eastern part Rahara is a much newer settlement. It used to be dense forest even 200 years back. The place was named after famous Portuguese dacoit "Rada" (pronunciation - Raw-ra) of late 17th Century.
Over time it became prosperous because of its proximity to Calcutta. One jamindar (landlord of a vast area) built 26 Shiv Temples here similar to Benaras so that people didn't have to go to Benaras. The majority of population work in service sector in nearby Calcutta. Some grow vegetables in the nearby fields. There are also some manufacturing units located on the main arterial road BT road. Rest are traders and there are many small trades in the area.
As of 2001[update] India census, Khardaha had a population of 116,252. Males constitute 53% of the population and females 47%. Khardaha has an average literacy rate of 81%, higher than the national average of 75%: male literacy is 83%, and female literacy is 79%. In Khardaha, 8% of the population is under 6 years of age. An overwhelming majority of the population is Hindu Bengali having fled from what is now Bangladesh following religious persecution in the hands of Muslims majority of that area. Bengali is the most widely spoken language, though Hindi and English is also understood.