Hanoi is the capital and second-most populous municipality of Vietnam. It covers an area of 3,358.6 km2 (1,296.8 mi2) and had a population of approximately 8.8 million as of 2025. In 2023, it recorded the second-highest gross regional domestic product among Vietnamese provinces and municipalities at US$48 billion.
The city serves as a major administrative and educational hub, hosting 78 foreign embassies, the headquarters of the Vietnam People's Army, the Vietnam National University system, and various other governmental organizations. Notable landmarks within or near the municipality include the Imperial Citadel of Thăng Long, Ho Chi Minh Mausoleum, Hoàn Kiếm Lake, West Lake, and Ba Vì National Park.
Hanoi's urban landscape features a diverse range of architectural styles resulting from 20th-century growth. These include French colonial architecture, brutalist apartments, and traditional disorganized alleys and tube houses. The city also saw significant tourism activity, welcoming 18.7 million domestic and international visitors in 2022.