The earliest tangible evidence of the history of Dehradun dates back to 300 BC, as indicated by a rock inscription at Kalsi, discovered in 1860. The inscriptions located at the northern outskirts of the city are attributed to King Ashoka. In the inscription, there are 14 edicts carved on a rock and adjacent to these is the site where Raja Shilvarma of the Vrisheri dynasty made three horse sacrifices during his rule in the 3rd century BC. At the site, large inscribed bricks are arranged to form the shape of a bird with a fire altar in the middle. There is no evidence of any kind of quite a long period after that, and the next prominent rulers of the valley were the Katyuris of Garhwal. Next, this stronghold of the Katyuri dynasty, passed into the hands of the Sikhs and Mughals and later, the Gorkhas of Nepal ruled here for a long time till the British came into the picture. For many centuries the region formed part of the Garhwal kingdom with some interruption from the Rohillas of the adjoining plains of Rohilkhand. For about two decades till 1815 it was under the occupation of the Gorkhas. In April 1815 Gorkhas were ousted from Garhwal region and Garhwal was annexed by the British. In that year the area now comprising tehsil Dehra Dun was added to district Saharanpur .

In 1825, however, it was transferred to the Kumaon Division. In 1828, Dehra Dun and Jaunsar Bhabar were placed under the charge of a separate Deputy Commissioner and in 1829, the Dehra Dun district was transferred from the Kumaon Division to the Meerut Division. In 1842, Dun was attached to Saharanpur district and placed under an officer subordinate to the Collector of the district but since 1871 it is being administered as separate district.

In 1968 the district was taken out from Meerut division and included in the Garhwal Division. According to the local legend, 'camp' refers to Ram Rai, son of Shri Hari Rai, the 7th guru of the Sikhs. Ram Rai founded a Gurudwara here, which is a pilgrimage centre for the Sikhs.

During British rule, Dehradun used to be the summer base for the Viceroy's bodyguards. In course of time, it was converted into an excellent centre for education and developed as a military cantonment.

Dehradun has a long and rich history. In Skanda Purana, this place has been mentioned as a part of Kedar Khand. By the end of the third century, it became a part of King Ashoka's vast empire. In subsequent centuries, it was a part of the Garhwal kingdom. In the beginning of the 19th century, for two decades, it was ruled by the Gorkhas. The Gorkha regime came to an end when the British captured this region in 1815.

Dehradun is known as the gateway to the majestic Himalayas . The mountain range lies to the north of the city while the sacred Ganga and Yamuna rivers embrace it from the east and west. Ganga enters Dehradun from the east at Tapovan and flows south-west to reach Haridwar via Raiwala and Rishikesh. Yamuna flows from the west down towards the south. The other rivers of the area are Asan, Tons, Bindal and Rispana.