French Indochina, officially known as the Indochinese Union and after 1947 as the Indochinese Federation, was a grouping of French colonial territories in Mainland Southeast Asia until its end in 1954. It comprised Cambodia, Laos, the Chinese territory of Guangzhouwan, and the Vietnamese regions of Tonkin in the north, Annam in the centre, and Cochinchina in the south. The capital for most of its history (1902–1945) was Hanoi; Saigon was the capital from 1887 to 1902 and again from 1945 to 1954.

Hanoi is the capital and second-most populous city of Vietnam. As evident by the literal translation of its name – 'inside the river' – portions of Hanoi's border are delineated by the Red and Black Rivers. As a municipality, Hanoi consists of 12 urban districts, 17 rural districts, and one district-level town. It has an area of 3,359.84 km2 (1,297.24 sq mi) and a population of 8,435,700 in 2022. In 2022, Hanoi has the second-highest gross regional domestic product of all Vietnam provinces and municipalities at 51.4 billion USD, behind Ho Chi Minh City. Hanoi Capital is also ASEAN 8th largest economy after Surabaya.