The Red Fort was the residence of the Mughal emperor of India for nearly 200 years, until 1857. It is located in the centre of Delhi and houses a number of museums. In addition to accommodating the emperors and their households, it was the ceremonial and political centre of Mughal government and the setting for events critically impacting the region.

The Red Fort, constructed by Shah Jahan, was built as the fortified palace of Shahjahanbad, capital of the fifth Mughal Emperor Shah Jahan in 1648. Named for its massive enclosing walls of red sandstone, it is adjacent to the older Salimgarh Fort, built by Islam Shah Suri in 1546. The imperial apartments consist of a row of pavilions, connected by a water channel known as the Stream of Paradise (Nahr-i-Behisht). The Red Fort is considered to represent the zenith of Mughal creativity under Shah Jahan. Although the palace was planned according to Islamic prototypes, each pavilion contains architectural elements typical of Mughal buildings, reflecting a fusion of Timurid, Persian and Hindu traditions. The Red Fort’s innovative architectural style, including its garden design, influenced later buildings and gardens in Delhi, Rajasthan, Punjab, Kashmir, Braj, Rohilkhand and elsewhere. With the Salimgarh Fort, it was designated a UNESCO World Heritage Site in 2007 as part of the Red Fort Complex.

Emperor Shah Jahan commissioned construction of the Red Fort in 1638, when he decided to shift his capital from Agra to Delhi. Its design is credited to architect Ustad Ahmad Lahauri, the same architect who constructed the Taj Mahal. The fort lies along the Yamuna River, which fed the moats surrounding most of the walls. Construction began in the sacred month of Muharram, on 13 May 1638. Supervised by Shah Jahan, it was completed in 1648. Unlike other Mughal forts, the Red Fort's boundary walls are asymmetrical to contain the older Salimgarh Fort. The fortress-palace was a focal point of the medieval city of Shahjahanabad, which is present-day Old Delhi. Its planning and aesthetics represent the zenith of Mughal creativity prevailing during Shah Jahan's reign. His successor  Aurangzeb added the Pearl Mosque to the emperor's private quarters, constructing barbicans in front of the two main gates to make the entrance to the palace more circuitous.

The Red Fort has an area of 254.67 acres (103.06  ha) enclosed by 2.41 kilometres (1.50  mi) of defensive walls, punctuated by turrets and bastions and varying in height from 18 metres (59  ft) on the river side to 33 metres (108  ft) on the city side. The fort is octagonal, with the north-south axis longer than the east-west axis. The marble, floral decorations and double domes in the fort's buildings exemplify later Mughal architecture. 

Its English name, "Red Fort", is a translation of the Hindustani  Lal Quila deriving from its red-sandstone walls. As the residence of the imperial family, the fort was originally known as the "Blessed Fort" (Quila-i-Mubarak). Agra Fort is also called Lal Quila.

The Red Fort is an iconic symbol of India. On the Independence Day of India (15 August), the Prime Minister of India hoists the national flag at the main gate of the fort and delivers a nationally-broadcast speech from its ramparts. 

Every year on the Independence Day of India (15 August), the Prime Minister of India hoists the national Flag at the Red Fort and delivers a nationally-broadcast speech from its ramparts. The Red Fort, the largest monument in Delhi, is one of its most popular tourist destinations and attracts thousands of visitors every year.