Uttar Pradesh (UP) is the most populated of the Indian states. The state capital city is Lucknow; other notable cities include Allahabad, Varanasi, Agra, Aligarh, Ayodhya, Etawah, Kanpur, Mirzapur and Deoband. Neighboring states are Uttaranchal, Rajasthan, Haryana, Bihar, Himachal Pradesh, Chhattisgarh, Madhya Pradesh, Jharkhand and Delhi. Uttar Pradesh also shares a border with Nepal. The world famous monument, Taj Mahal is situated in Agra, Uttar Pradesh.

In 2000, the northern hilly region of Uttar Pradesh was carved off to form the state of Uttaranchal. Uttar Pradesh covers a large part of the densely populated plains around the Ganges and Yamuna. With 166 million inhabitants, it is not only the most populous state in India, but also the most populous sub-national entity in the world. Only five countries of the world, China, India itself, the United States, Indonesia and Brazil, have a higher population than Uttar Pradesh. It is also one of the most economically backward states of India. The literacy rate, as is the case with the rest of India, is higher for males than females.

It covers the area of the old princely state of Oudh and the British Province of Agra. They were merged in 1858 to form the United Provinces of Agra and Oudh, later known as United Provinces. After independence, it was renamed Uttar Pradesh to retain the short form UP, by which it is best known in India. The state comprises the regions of Rohilkhand in the northwest, Brij (Braj) in the southwest, Awadh (Oudh) in the centre, Bundelkhand in the south and Purvachal in the east.

The languages and customs of the different regions are distinct, and the dialect of the western regions (Khadiboli) is the basis for the official Hindi language. Urdu is also widely spoken in large parts of Uttar Pradesh.

The former Prime Minister of India, Atal Behari Vajpayee, represents the parliamentary constituency of Lucknow.