Archaeological evidence support the existence of humans in the region since prehistoric times. The region formed a part of the Kuru and the Panchal kingdoms (mahajanpads) during the Vedic age of ancient India. Among the first major dynasties of Garhwal and Kumaon were the Kunindas in the 2nd century BCE who practised an early form of Shaivism. Ashokan edicts at Kalsi show the early presence of Buddhism in this region. During the medieval period the region was consolidated under the Kumaon Kingdom and Garhwal Kingdom. By 1803 the region fell to the Gorkha Empire of Nepal and with the conclusion of the Anglo-Nepalese War in 1816 most of modern Uttarakhand was ceded to the British as part of the Treaty of Sugauli. Although the erstwhile hill kingdoms of Garhwal and Kumaon were traditional rivals, the proximity of different neighbouring ethnic groups and the inseparable and complementary nature of their geography, economy, culture, language, and traditions created strong bonds between the two regions which further strengthened during the Uttarakhand movement for statehood in the 1990s.
The natives of the state are generally called Uttarakhandi or more specifically either Garhwali or Kumaoni depending on their place of origin. According to the 2011 Census of India, Uttarakhand has a population of 10,116,752, making it the 19th most populous state in India. A large portion of the population consists of Rajputs and Brahmins. About 85% of the population follow Hinduism. Islam is the largest minority religion in the state, followed by Sikhism, Christianity, Buddhism, and Jainism. Garhwali and Kumaoni along with other hilly dialects and sub-dialects are the main regional languages, whereas Hindi is the most widely spoken language. Uttarakhand is the only state in India with Sanskrit as one of its official languages.
Uttarakhand is also well known for the mass agitation of the 1990s that led to the formation of the Chipko environmental movement and other social movements. Though primarily a livelihood movement rather than a forest conservation movement, it went on to become a rallying point for many future environmentalists, environmental protests, and movements the world over and created a precedent for non-violent protest. It stirred up the existing civil society in India, which began to address the issues of tribal and marginalized people. So much so that, a quarter of a century later, India Today mentioned the people behind the "forest satyagraha" of the Chipko movement as amongst "100 people who shaped India". One of Chipko's most salient features was the mass participation of female villagers. Both female and male activists played pivotal roles in the movement, including Chandi Prasad Bhatt, Sundarlal Bahuguna, and Ghanshyam Raturi, the popular Chipko poet.