Taipei City is the capital of the Taiwan and the central city of the largest metropolitan area of Taiwan. Situated at the northern tip of the island, Taipei is located on the Danshui River, and is about 25 km southwest of Keelung, its port on the Pacific Ocean. Another coastal city, Danshui, is about 20 km northwest at the river's mouth on the Taiwan Strait. It lies in the two relatively narrow valleys of the Keelung (基隆河) and Xindian (新店溪) rivers, which join to form the Danshui River along the city's western border. The city proper (Taipei City) is home to an estimated 2,618,772 people. Taipei, New Taipei, and Keelung together form the Taipei metropolitan area with a population of 6,900,273.However, they are administered under different local governing bodies. "Taipei" sometimes refers to the whole metropolitan area, while "Taipei City" refers to the city proper. Taipei City proper is surrounded on all sides by New Taipei.

Taipei has 47 sister cities , 1 partner city and 2 friendship cities.