Lakhimpur Kheri is the largest district in Uttar Pradesh, India, on the border with Nepal. Its administrative capital is the city of Lakhimpur.

Lakhimpur Kheri district is a part of Lucknow division, with a total area of 7,680 square kilometres (2,970 sq mi).The national government designated Lakhimpur Kheri as a Minority Concentrated District on the basis of 2001 census data, which identifies it as requiring urgent aid to improve living standards and amenities.

Dudhwa National Park, is in Lakhimpur Kheri and is the only national park in Uttar Pradesh.It is home to a large number of rare and endangered species including tigers, leopards, swamp deer, hispid hares and Bengal floricans.

Kheri is a town 2 kilometres (1.2 mi) from Lakhimpur. It has the name derived from a tomb built over the remains of Saiyid Khurd, who died in 1563. Pre-independence the tomb was administered under Act XX of 1856, with an income of about ₹ 800. Another theory suggests that the name derives from the khair trees that once covered large tracts in the area.

Traditions point to the inclusion of this place under the rule of the Lunar race of Hastinapur, and several places are associated with episodes in the Mahabharata.Many villages contain ancient mounds in which fragments of sculpture have been found, Balmiar-Barkhar and Khairlgarh being the most remarkable. A stone horse was found near Khairabad and bears the inscription of Samudra Gupta, dated in the 4th century. Samudra Gupta, King of Magadha performed Ashvamedha yajna in which a horse is left to freely roam in the entire nation, so as to display the power of king and to underline the importance of his conquest. The stone replica of the horse, is now in the Lucknow Museum.

The northern part of Lakhimpur Kheri was held by Rajputs in the 10thcentury. Muslim rule spread slowly to this remote and inhospitable tract. In the 14th century several forts were constructed along the northern frontier, to prevent the incursions of attacks from Nepal.

During the Mughal Empire in the 17th century, under the rule of Akbar the district formed part of the Sarkar of Khairabad in the Subah of Oudh. The later history of 17th century under the Nawabs of Awadh, is of the rise and decline of individual ruling families.

The district is within the Terai lowlands at the base of the Himalayas, with several rivers and lush green vegetation. Situated between 27.6° and 28.6° north latitude and 80.34° and 81.30° east longitudes, and about 7,680 square kilometres (2,970 sq mi) in area, it is roughly triangular in shape, the flattened apex pointing north. The district is located at about the height of 147 meters above sea level.Lakhimpur Kheri is bounded on the north by the river Mohan, separating it from Nepal; on the east by the Kauriala river, separating it from Bahraich; on the south by Sitapur and Hardoi; and on the west by Pilibhit and Shahjahanpur.

In 2006 the Ministry of Panchayati Raj named Lakhimpur Kheri one of the country’s 250 most backward districts (out of a total of 640).It is one of the 34 districts in Uttar Pradesh currently receiving funds from the Backward Regions Grant Fund Programme (BRGF).

According to the 2011 census Lakhimpur Kheri District has a population of 4,021,243 roughly equal to the nation of Liberia or the US state of Oregon.This gives it a ranking of 56th in India (out of a total of 640).The district has a population density of 523 inhabitants per square kilometre (1,350/sq mi).Its population growth rate over the decade 2001–2011 was 25.38%.Kheri has a sex ratio of 894 females for every 1000 males, and a literacy rate of 60.56%.Languages spoken here include Awadhi, a vernacular in the Hindi dialect continuum spoken by over 38 million people, mainly in the Awadh region.

Dudhwa Tiger Reserve in Lakhimpur Kheri has two core areas, Dudhwa National Park[57] and Kishanpur Wildlife Sanctuary, which were merged in 1987. Dudhwa National Park is known as the first National Park of the state after the formation of Uttarakhand and is a national protected area. It is home to a large number of rare and endangered species including tigers, leopards, rhinoceros, hispid hare, elephants, black deer and swamp deer. Dudhwa has approximately 400 species of birds including egrets, cormorants, herons and several species of duck, goose and teal. Its swamps and lakes are particularly attractive to water birds, including varieties that migrate here from the Himalayas to spend the winter months. Bird watching is popular at the Banke Tal.

According to the 2011 census, Lakhimpur Kheri district had a literacy rate of 60.56% up from 48.39% in 2001, male and female literacy were 69.57% and 50.42% respectively.In the 2001 census, same figures stood at 59.50% and 35.38% in Kheri District. Total literate in the district were 2,034,044 of which male and female were 1,237,157 and 796,887 respectively.The growth of literacy in the last decade of the twentieth century was particularly remarkable with special emphasis on the eradication of illiteracy.

Lakhimpur’s most popular sport is cricket and it has several League cricket clubs. Other sports being actively played include football, hockey, basketball and badminton. Schools and colleges organise the sports activities, teams play in inter-school and inter-city tournaments.