The High Court of Judicature at Allahabad is a constitutional institution and the highest court of justice for the state of Uttar Pradesh, with its principal seat in Prayagraj and a permanent bench in Lucknow. Its origin dates back to the British era, established on 17 March 1866, as the High Court of Judicature for the North-Western Provinces at Agra, under the Indian High Courts Act, 1861. This Act replaced the older judicial system, including the Sadr Diwani Adalat. The court's seat was shifted to Allahabad in 1869, and its name was officially changed to 'the High Court of Judicature at Allahabad' by a supplementary Letters Patent on 11 March 1919.
The court's present status was secured by the United Provinces High Courts (Amalgamation Order), 1948, which merged the Chief Court of Oudh at Lucknow with the Allahabad High Court, effective from 19 July 1948. It functions under the authority of the Constitution of India, which affirms its existence under Article 214. The court exercises its power to issue writs for the protection of fundamental and legal rights under Article 226 and supervises all subordinate courts and tribunals in the state under Article 227. It is one of the largest High Courts in India, with a sanctioned strength of up to 160 judges. A significant recent change occurred on 9 November 2000, when the Uttarakhand High Court was established, causing the Allahabad High Court to cease jurisdiction over the 13 districts that formed the new state of Uttarakhand.