Kathmandu (Nepali: काठमांडौ, ) is the capital and largest metropolitan city of Nepal. The city is the urban core of the Kathmandu Valley in the Himalayas, which also contains two sister cities namely Patan or Lalitpur, 5 kilometres (3.1 mi) to its southeast (an ancient city of fine arts and crafts) and Bhaktapur, 14 kilometres (8.7 mi) to its east (city of devotees). It is also acronymed as 'KTM' and named 'tri-city'.

The city stands at an elevation of approximately 1,400 metres (4,600 ft) in the bowl-shaped valley in central Nepal surrounded by four major mountains, namely: Shivapuri, Phulchowki, Nagarjun and Chandragiri. It is inhabited by 671,846 (2001) people. The Kathmandu valley with its three districts including Kathmandu District accounts for a population density of only 97 per km² whereas Kathmandu metropolitan city has a density of 13,225 per km². It is by far the largest urban agglomerate in Nepal, accounting for 20% of the urban population in an area of 5,067 hectares (12,520 acres) (50.67 square kilometres (19.56 sq mi)).
Kathmandu is not only the capital of the Federal Democratic Republic of Nepal but also the headquarters of the Central Region (Madhyamanchal) among the five development regions constituted by the 14 administrative zones of Nepal located at the central part of the country. The Central region has three zones namely, Bagmati, Narayani and Janakpur. Kathmandu is located in the Bagmati Zone.