Lý Thái Tổ in the context of Vietnamese name

Hanoi (/hæˈnɔɪ/ han-OY; Vietnamese: Hà Nội [hàː nôjˀ] ) is the capital and second-most populous city of Vietnam. The name "Hanoi" translates to "inside the river" (Hanoi is bordered by the Red and Black Rivers). The city encompasses an area of 3,358.6 km (1,296.8 sq mi), and as of 2025 has a population of 8,807,523. Hanoi had the second-highest gross regional domestic product of all Vietnamese provinces and municipalities at US$48 billion in 2023, behind only Ho Chi Minh City.

In the third century BCE, the Cổ Loa Capital Citadel of Âu Lạc was constructed in what is now Hanoi. Âu Lạc then fell under Chinese rule for a thousand years. In 1010, under the Lý dynasty, Vietnamese emperor Lý Thái Tổ established the capital of the imperial Vietnamese nation Đại Việt in modern-day central Hanoi, naming the city Thăng Long [tʰɐŋ loŋ], 'ascending dragon'). In 1428, King Lê Lợi renamed the city to Đông Kinh [ɗoŋ kīŋ̟], 'eastern capital'), and it remained so until 1789. The Nguyễn dynasty in 1802 moved the national capital to Huế and the city was renamed Hanoi in 1831. It served as the capital of French Indochina from 1902 to 1945 and French protectorate of Tonkin from 1883 to 1949. After the August Revolution and the fall of the Nguyễn dynasty, the Democratic Republic of Vietnam (DRV) designated Hanoi as the capital of the newly independent country. From 1949 to 1954, it was part of the State of Vietnam. It was again part of the DRV ruling North Vietnam from 1954 to 1976. In 1976, it became the capital of the unified Socialist Republic of Vietnam. In 2008, Hà Tây Province and two other rural districts were annexed into Hanoi, almost tripling Hanoi's area.

Hanoi (/hæˈnɔɪ/ han-OY; Vietnamese: Hà Nội [hàː nôjˀ] ) is the capital and second-most populous city of Vietnam. The name "Hanoi" translates to "inside the river" (Hanoi is bordered by the Red and Black Rivers). The city encompasses an area of 3,358.6 km (1,296.8 mi), and as of 2025 has a population of 8,807,523. Hanoi had the second-highest gross regional domestic product of all Vietnamese provinces and municipalities at US$48 billion in 2023, behind only Ho Chi Minh City.

In the third century BCE, the Cổ Loa Capital Citadel of Âu Lạc was constructed in what is now Hanoi. Âu Lạc then fell under Chinese rule for a thousand years. In 1010, under the Lý dynasty, Vietnamese emperor Lý Thái Tổ established the capital of the imperial Vietnamese nation Đại Việt in modern-day central Hanoi, naming the city Thăng Long [tʰɐŋ loŋ], 'ascending dragon'). In 1428, King Lê Lợi renamed the city to Đông Kinh [ɗoŋ kīŋ̟], 'eastern capital'), and it remained so until 1789. The Nguyễn dynasty in 1802 moved the national capital to Huế and the city was renamed Hanoi in 1831. It served as the capital of French Indochina from 1902 to 1945 and French protectorate of Tonkin from 1883 to 1949. After the August Revolution and the fall of the Nguyễn dynasty, the Democratic Republic of Vietnam (DRV) designated Hanoi as the capital of the newly independent country. From 1949 to 1954, it was part of the State of Vietnam. It was again part of the DRV ruling North Vietnam from 1954 to 1976. In 1976, it became the capital of the unified Socialist Republic of Vietnam. In 2008, Hà Tây Province and two other rural districts were annexed into Hanoi, almost tripling Hanoi's area.

The Imperial Citadel of Thăng Long (Vietnamese: Hoàng thành Thăng Long; chữ Hán: 皇城昇龍) is a complex of historic buildings associated with the history of Vietnam located in the centre of Hanoi, Vietnam. Its construction began in 1010 and was completed in early 1011 under the reign of Emperor Lý Thái Tổ of the Lý dynasty. Most of the existing structure is dated to the extensive reconstruction of the old Imperial Citadel ordered by Gia Long in 1805, but the Citadel (except for the North Gate and the Flag Tower) was largely demolished by the French to allow more land for offices and barracks.