Kathmandu is the capital and, with more than one million inhabitants, the largest metropolitan city of Nepal. The city is the urban core of the Kathmandu Valley in the Himalayas, which contains two sister cities: Lalitpur (Patan), 5 kilometres (3.1 mi) to its south and Bhaktapur or Bhadgaon, 12 kilometres (7.5 mi) to its east, and a number of smaller towns. It is also acronymed as \\\'KTM\\\' and named \\\'tri-city\\\'.In the last census (2001), the city of Kathmandu had 671,846 inhabitants. Population estimates for 2005 were 790,612 for 2010 they stood at 989,273 and 2012 at 1,006,656 The municipal area is (50.67 square kilometres (19.56 sq mi)) and the population density is 19,500 per km².
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: Shivapuri, Phulchoki, Nagarjun, and Chandragiri. Kathmandu valley is part of three districts, Kathmandu District, Lalitpur District and Bhaktapur District, with the highest population density in the country and accounting for about 1/12 of its population. These three districts contain 2.5 million people, as of the 2011 census.
Historically, only the Kathmandu Valley was referred to as "Nepal" by people who lived outside the valley. After the annexation of the valley by the Gorkha kingdom, and subsequent conversion of the valley as the capital of their empire, this designation of "Nepal" was extended to every land they conquered. The valley itself was referred to as "Nepal Proper" by the contemporary British historians. Today 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: Bagmati, Narayani and Janakpur. Kathmandu is located in the Bagmati Zone.
Kathmandu, as the gateway to Nepal Tourism, is the nerve centre of the country’s economy. With the most advanced infrastructure among urban areas in Nepal, Kathmandu\\\'s economy is tourism centric accounting for 3.8% of the GDP in 1995–96 (had declined since then due to political unrest but has picked up again).
The city has rich history spanning nearly 2000 years, as inferred from an inscription in the valley. Most of Kathmandu\\\'s people follow Hinduism followed by Buddhism. People of other religious beliefs also live in Kathmandu giving it a cosmopolitan culture. Nepali is the most common language of the city. Nepal Bhasa is the indigenous language spoken by the Newar people. Hindi is widely understood. English is understood by the educated population of the city. The literacy rate is 98% in the city.
From the point of view of tourism, economy and cultural heritage, the sister cities of Lalitpur (Patan) and Bhaktapur are integral to Kathmandu. The cultural heritage recognition under the World Heritage list of the UNESCO has recognized all the monuments in the three cities as one unit under the title "Kathmandu Valley-UNESCO World Heritage Site".