Solan is a city and a Municipal Corporation in Solan district (created on 1 September 1972) in the Indian state of Himachal Pradesh. It is located 50 kilometres (31 mi) south of the state capital Shimla. The place is named after the Hindu goddess Shoolini devi. Every year in the month of June, a fair celebrating the goddess is held, featuring a 3-day mela at the central Thoudo grounds. Solan was the capital of the erstwhile princely state, Bhagat. It is known as the "Mushroom city of India" because of the vast mushroom farming in the area as well as the mushroom research centre situated at Chambaghat. Solan is also called the "City of Red Gold", in reference to the bulk production of tomatoes in the area.
The city of Solan is spread over an area of 33.43 km2, which makes it the largest city in Himachal Pradesh by land area, followed by the city of Shimla, with an area of 31.60 km2. It is the second most populous city of Himachal Pradesh after Shimla.
The town is situated between Chandigarh (joint capital of Punjab and Harayana) and Shimla (state capital), on the Kalka-Shimla National Highway-22. The Kalka-Shimla narrow gauge heritage railway line, built by the British passes through Solan.