The most populous city in Taiwan is New Taipei City, with a population of over 4.03 million.

New Taipei City, one of the six municipalities in Taiwan Province of China, is located in the northernmost tip of Taiwan Island, the whole territory around Taipei City, the northeast is surrounded by Keelung City, Taiwan Province of three sides, southeast of Taiwan Province of Yilan County, southwest of Taoyuan City. It has 29 districts with a total area of 2,052.6 square kilometers, and is the largest city in Taiwan.

The economic industries of New Taipei City are mainly finance, commerce, service, industry, catering, and tourism. New Taipei City is a multi-core city in the sub-center of the Taipei metropolitan area, with a large population and a large number of immigrants from all over Taiwan. There are highly urbanized areas, as well as countryside and natural mountainous and riverine landscapes, with a diverse landscape, demographic composition, and economic and industrial diversities, which is a microcosm of the society of the Taiwan region.

New Taipei City

New Taipei City is located in the northern tip of Taiwan Province, bordering Taoyuan City in the west and south, Yilan County in the east, the Pacific Ocean and the East China Sea in the northeast, and the Taiwan Straits in the northwest, with Taipei City in the center surrounded by the city, and Keelung City in the northeast.

The center of the city is Shidin District, the extreme east point is Lailai in Tianliao Yang of Gongliao District, the extreme west point is Xiaofu in Xiaonanwan of Linkou District, the extreme south point is Qilan Mountain of Wulai District, and the extreme north point is Fugui Jiao of Shimen District; the land spans longitude 122°01′26″-121°16′31″E, latitude 24°40′51″N -25°18′11″N -25°18′11″, 69.09 kilometers in length from north to south, 68.4 kilometers in width from east to west, with a total land area of 2052.5923 square kilometers.

Reference for the above: Baidu Encyclopedia-New Taipei City