The town takes its name from Kalika maa the ruling deity. Kalka was acquired by British India from the Princely state of Patiala in 1843 as a depot for Simla, the summer capital of the Raj. It became the junction for the Delhi-Ambala-Kalka, and the Kalka - Simla railways. By 1901, the town, administered as a notified area, had a population of 7,045, a railway workshop, and was a market for ginger and turmeric. The Kalka municipal committee was created on 11 April 1933.
Kalka experiences a subtropical climate, with a monsoon season from late June to early October. The summer starts in mid-April and temperatures peak during May and June. This is followed by the monsoon season, which is accompanied by a drop in temperature and an increase in humidity. Temperatures remain moderate in October and November, but start falling towards the end of November. Winter lasts through December, January and February, with temperatures lowest in early January. Kalka also receives some rainfall from Western Disturbance, near the end of winter. Winter season, despite being chilly, is mostly free of fog unlike most North Indian cities in the plains.
Kalka is situated along a slope. This makes it somewhat difficult to commute on foot. Local transport (within Kalka) is by shared auto-rickshaws. These autos ply to a distance of around 15–20 km. There are also shared cabs (not the luxury ones) for distances up to 25–30 km. Government and private buses are also very common for commuting to nearby cities. Many intercity govt buses start or pass through Kalka, connecting it with Chandigarh, Ambala, Delhi, Shimla and many other cities.
Kalka railway station is the northern terminal of the Delhi-Kalka line of Northern Railway, Indian Rail (Station code KLK) serving as terminal station for broad gauge line (towards Chandigarh) and narrow gauge line (towards Shimla). Direct trains on broad gauge, connect to Delhi, Mumbai, Howrah etc.
The Kalka Shimla Railway features on the UNESCO's World Heritage sites list as the Mountain Railways of India. Work on the railway line started in 1898 and it opened for traffic in 1903.
According to 2011 census the population of Kalka is 30,314
The ancient temple of the Hindu goddess Kali is situated on the National Highway 22 that runs through Kalka town. The temple is very popular with hundreds of devotees pay their respects annually during the Navratri. It is believed that this temple was built in the age of Mahabhrata by Pandvas, during "Agyat Vas" when they stayed here for some time.
Sri Trimurti Dham is situated amidst the beautiful mountain ranges of shivalik hills - like the jewel in the crown - on the pictureque hill-top beside the eastern fringe of Kalka village in distt. Panchkula (Haryana) overlooking the industrial city Parwanoo which is serving as the gateway to the scenic beauty and grandeur of the mighty Himalyas of Himachal Pardesh. The literal meaning of 'Sri Trimurti Dham' is "a place where Teen Murtis (three idols) exist together".Shri Bala ji Hanuman, Shri Pretraj Sarkar and Shri Bhairav ji. http://www.sritrimurtidham.org/
The Yadavindra Gardens at Pinjore, believed to be built by Mughals, is another popular destination among people visiting the area. Every year a Mango Mela is organised here in which 500 varieties of mangoes are displayed for the visitors. There are many buildings which was made by Mughals and was of greenery only.