Taipei–Keelung metropolitan area in the context of "Taoyuan–Zhongli metropolitan area"

Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main island of Taiwan, also known as Formosa, lies between the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeast, and the Philippines to the south. It has an area of 35,808 square kilometres (13,826 square miles), with mountain ranges dominating the eastern two-thirds and plains in the western third, where its highly urbanized population is concentrated. The combined territories under ROC control consist of 168 islands in total covering 36,193 square kilometres (13,974 square miles). The largest metropolitan area is formed by Taipei (the capital), New Taipei City, and Keelung. With around 23.9 million inhabitants, Taiwan is among the most densely populated countries.

Taiwan has been settled for at least 25,000 years. Ancestors of Taiwanese indigenous peoples settled the island around 6,000 years ago. In the 17th century, large-scale Han Chinese immigration began under Dutch colonial rule and continued under the Kingdom of Tungning, the first predominantly Han Chinese state in Taiwanese history. The island was annexed in 1683 by the Qing dynasty and ceded to the Empire of Japan in 1895. The Republic of China, which had overthrown the Qing in 1912 under the leadership of Sun Yat-sen, assumed control following the surrender of Japan in World War II. But with the loss of mainland China to the Communists in the Chinese Civil War, the government moved to Taiwan in 1949 under the Kuomintang (KMT).

Taipei (/ˌtaɪˈpeɪ/ ; traditional Chinese: 臺北; simplified Chinese: 台北; pinyin: Táiběi pronounced:[tʰǎɪpèɪ]), officially Taipei City, is the capital and a special municipality of Taiwan. Located in Northern Taiwan, Taipei City is an enclave of the municipality of New Taipei City that sits about 25 km (16 mi) southwest of the northern port city of Keelung. Most of the city rests on the Taipei Basin, an ancient lakebed. The basin is bounded by the relatively narrow valleys of the Keelung and Xindian rivers, which join to form the Tamsui River along the city's western border.

The municipality of Taipei is home to an estimated population of 2,494,813 (March 2023), forming the core part of the Taipei–Keelung metropolitan area, also known as "Greater Taipei", which includes the nearby cities of New Taipei and Keelung with a population of 7,047,559, the 40th most-populous urban area in the world—roughly one-third of Taiwanese citizens live in the metro areas. The name "Taipei" can refer either to the whole metropolitan area or just the municipality alone. Taipei has been the political center of the island since 1887, when it first became the seat of Taiwan Province by the Qing dynasty until 1895 and again from 1945 to 1956 by the Republic of China (ROC) government, with an interregnum from 1895 to 1945 as the seat of the Government-General of Taiwan during the Japanese rule. The city has been the national seat of the ROC central government since 1949, and it became the nation's first special municipality (then known as Yuan-controlled municipality) on 1 July 1967, upgrading from provincial city status.

Keelung (/kiːˈlʊŋ/ kee-LUUNG; Chinese: 基隆; pinyin: Jīlóng; Pe̍h-ōe-jī: Ke-lâng), Chilung or Jilong (/dʒiːˈlʊŋ/ jee-LUUNG), officially known as Keelung City, is a major port city in northeastern Taiwan. The city is part of the Taipei–Keelung metropolitan area with neighboring New Taipei City and Taipei. Nicknamed the Rainy Port for its frequent rain and maritime role, the city is Taiwan's second largest seaport (after Kaohsiung), and was the world's 7th largest port in 1984.

In 1626, the Spanish established Fort San Salvador at present-day Keelung, an area inhabited by Taiwanese indigenous peoples. Control of the area eventually passed to the Qing dynasty. Fighting between China and Europeans around Keelung occurred in the 19th century during the First Opium War and the Sino-French War. The island of Taiwan was ceded to the Empire of Japan in 1895 after the First Sino-Japanese War; under Japanese rule the city was called Kirun. Keelung became part of Taiwan Province under the Republic of China after 1945. Administratively, the city became a first-level subdivision in 2018 after the provincial government was abolished.