Solan district derives its name from Solan town which came into existence after the construction of a cantonment around the last quarter of the 19th century. Solan district is bounded by Shimla district in the North, by Ropar district of Punjab and Ambala district of Haryana in the south, by Sirmaur district in the east and by Bilaspur district in the west. Mandi district touches the boundary of Solan district in north-east. Solan is located between the longitudes 76.42 and 77.20 degree and latitudes 30.05 and 31.15 degree north. The elevation of the district ranges from 300 to 3000 m. The mountain ranges lie in the outer Himalayas and are a part of Shivalik ranges. The total area of the district is 1,936 sq km and the total population is 5,00,557.

Solan became a district of Himachal Pradesh on 1st September, 1972. It was carved out of Solan and Arki tehsils of the then Mahasu district and Kandaghat and Nalagarh tehsils of the then Shimla district. The district is divided into four sub-divisions (Solan, Nalagarh, Arki and Kandaghat), five tehsils (Arki, Kandaghat, Kasauli, Nalagarh and Solan) and two sub-tehsils (Kuthar and Ramshehar).
 
The Solan district comprises of the erstwhile princely states of Bhagal, Bhagat, Kunihar, Kuthar, Mangal, Beja, Mahlog, Nalagarh and parts of Keonthal and Kothi. Most of these princely states were subjected to Gurkha attacks from 1803 to 1805. In 1815 the Gurkhas lost to the British, and these states were restored to the respective rulers. Himachal Pradesh appeared on the administrative map of India in 1948 and the states of Bhagat, Baghal, Kunihar, Kuthar, Mangal, Beja, Keonthal and Koti formed a part of the then Mahasu district. After Independence, Nalagarh state was merged in the then combined Punjab state and remained a tehsil of Ambala district

The important towns in the district are Solan, Baddi, Nalagarh, Parwanoo, Subathu, Kasauli, Arki and Dagshai. Kasauli (1800 m), Chail (2200 m), Barog (1600 m) and Dagshai (1750 m) are the popular hill stations and visited by tourists all the year round. Solan town, Baddi, Nalagarh and Parwanoo are important industrial centres of the district. The famous Mohan Meakin's brewery, situated in Solan district, is reputed to be India's oldest brewery.

Besides the Dr. Y S Parmar University of Horticulture and Forestry at Nauni, other places of interest in Solan include the Shoolini Mata temple (Solan is named after the goddess Shoolini), the Jatoli Shiv temple and the Yungdrung Tibetan Monastery, also near Nauni. The Fort Palace at Arki was built by Prithvi Singh, the then ruler of Bhagal state between 1695-1700. This Fort was also the Headquarter of the Gurkha General Amar Singh Thapa from 1806-1815. Another famous monument in Solan district, the Chail Palace, was built in 1891 by Maharaja Bhupendra Singh, the then ruler of Patiala state. Chail also boasts of one of the highest cricket playing fields in the world.

Most of the people living in Solan district are Hindus, followed by Sikhs and Buddhists. The main languages used are Hindi, English, Pahari and Punjabi.