Kathmandu (Nepali: [ˌkaʈʰmaɳˈɖu]) is the capital and largest city of Nepal, situated in the central part of the country within the Kathmandu Valley. As per the 2021 Nepal census, it has a population of 845,767 residing in 105,649 households, with approximately 4 million people in the surrounding metropolitan area. The city stands at an elevation of 4,344 feet (1,324 metres) above sea level.

Recognized as one of the oldest continuously inhabited places in the world, Kathmandu's history dates back to the 2nd century AD. Historically known as the Nepal Mandala, the valley has been the cultural and political hub for the Newar people, a significant urban civilization in the Himalayan region. Kathmandu served as the royal capital of the Kingdom of Nepal and is home to numerous palaces, temples, and gardens reflecting its rich heritage. Since 1985, it has hosted the headquarters of the South Asian Association for Regional Cooperation (SAARC).

Today, Kathmandu remains the epicenter of Nepal's history, art, culture, and economy. It has a multi-ethnic population with a Hindu majority. Religious and cultural festivals are integral to life in the city. Tourism plays a vital role in the economy, with the city serving as a gateway to the Nepal Himalayas. Kathmandu is home to several World Heritage Sites, including the Durbar Square, Swayambhu Mahachaitya, Bouddha, and Pashupatinath.

The Kathmandu Valley has been experiencing rapid urbanization, with a growth rate of 4% per year as of 2010, making it one of the fastest-growing metropolitan areas in South Asia. This expansion presents both opportunities and challenges in terms of infrastructure, sustainability, and planning.