Uttar Pradesh (; Hindustani: [ˈʊtːəɾ pɾəˈdeːʃ] (listen), lit. 'Northern Province') is a state in northern India. With over 240 million inhabitants, it is the most populated state in India as well as the most populous country subdivision in the world. It was established in 1950 after India had become a republic. It was a successor to the United Provinces (UP) during the period of the Dominion of India (1947–1950), which in turn was a successor to the United Provinces (UP) established in 1935, and eventually of the United Provinces of Agra and Oudh established in 1902 during the British Raj. The state is divided into 18 divisions and 75 districts, with the state capital being Lucknow, and Allahabad (Prayagraj) serving as the judicial capital. On 9 November 2000, a new state, Uttaranchal (now Uttarakhand), was created from Uttar Pradesh's western Himalayan hill region. The two major rivers of the state, the Ganges and its tributary Yamuna, meet at the Triveni Sangam in Allahabad, a Hindu pilgrimage site. Other notable rivers are Gomti and Saryu. The forest cover in the state is 6.1 per cent of the state's geographical area. The cultivable area is 82 per cent of total geographical area and net area sown is 68.5 per cent of cultivable area.

The state is bordered by Rajasthan to the west, Haryana, Himachal Pradesh and Delhi to the northwest, Uttarakhand and an international border with Nepal to the north, Bihar to the east, Madhya Pradesh to the south, and touches the states of Jharkhand and Chhattisgarh to the southeast. It covers 240,928 km² (93,023 sq mi), equal to 7.3% of the total area of India, and is the fourth-largest Indian state by area. Though long known for sugar production, the state's economy is now dominated by the services industry. The service sector comprises travel and tourism, hotel industry, real estate, insurance and financial consultancies. The economy of Uttar Pradesh is the third-largest state economy in India with ₹18.63 lakh crore (US$230 billion) in gross domestic product and a per capita GSDP of ₹68,810 (US$860). President's rule has been imposed in Uttar Pradesh ten times since 1968, for different reasons and for a total of 1,700 days. The state has currently three international airports – Chaudhary Charan Singh International Airport (Lucknow), Lal Bahadur Shastri Airport (Varanasi) and Kushinagar International Airport (Kushinagar). Prayagraj Junction is the headquarters of the North Central Railway and Gorakhpur Railway Station serves as the headquarters of the North Eastern Railway. The High Court of the state is located in Allahabad. The state contributes 80 seats and 31 seats to the lower house Lok Sabha and the upper house Rajya Sabha, respectively.

Inhabitants of the state are called either Awadhi, Bagheli, Bhojpuri (Purvanchali), Braji, Bundeli, Kannauji, or Rohilkhandi depending upon their region of origin. Hinduism is practised by more than three-fourths of the population, with Islam being the next largest religious group. Hindi is the most widely spoken language and is also the official language of the state, along with Urdu. Bhojpuri is the second most widely spoken language of the state after Hindi. Uttar Pradesh was home to most of the mainstream political entities that have existed in ancient and medieval India including the Maurya Empire, Harsha Empire, Gupta Empire, Pala Empire, Delhi Sultanate, Mughal Empire as well as many other empires. At the time of Indian independence movement in the early 20th century, there were three major princely states in Uttar Pradesh – Ramgadi, Rampur and Benares. The state houses several holy Hindu temples and pilgrimage centres. Uttar Pradesh has three World Heritage sites. Uttar Pradesh has several historical, natural, and religious tourist destinations, including Agra, Aligarh, Ayodhya, Kushinagar, Mathura, Allahabad, Varanasi and Vrindavan.