Beijing, alternatively romanized as Peking, is the capital of the People's Republic of China. It is the center of power and development of the country.

Beijing is the world's most populous national capital city, with over 21 million residents. It has an administrative area of 16,410.5 km2 (6,336.1 sq mi), the third in the country after Guangzhou and Shanghai.

It is located in Northern China, and is governed as a municipality under the direct administration of the State Council with 16 urban, suburban, and rural districts. Beijing is mostly surrounded by Hebei Province with the exception of neighboring Tianjin to the southeast; together, the three divisions form the Jingjinji megalopolis and the national capital region of China.

Beijing is a global city and one of the world's leading centres for culture, diplomacy, politics, finance, business and economics, education, research, language, tourism, media, sport, science and technology and transportation.

As a megacity, Beijing is the second largest Chinese city by urban population after Shanghai. It is home to the headquarters of most of China's largest state-owned companies and houses the largest number of Fortune Global 500 companies in the world, as well as the world's four biggest financial institutions by total assets. It is also a major hub for the national highway, expressway, railway, and high-speed rail networks.

The Beijing Capital International Airport has been the second busiest in the world by passenger traffic (Asia's busiest) since 2010, and, as of 2016, the city's subway network is the busiest and longest in the world. The Beijing Daxing International Airport, a second international airport in Beijing, is the largest single-structure airport terminal in the world.