Keelung was first inhabited by the Ketagalan, a tribe of Taiwanese aborigine. Its first contact with the west was with the Spanish in the early 17th century, who built a fort in Keelung as an outpost of the Manila-based Spanish East Indies. From 1642 to 1661 and 1663–1668, Keelung was under Dutch control. The Dutch East India Company took over the Spanish Fort San Salvador at Santissima Trinidad. They reduced its size and renamed it Fort Noort-Hollant. The Dutch had three more minor fortifications in Keelung and also a little school and a preacher. When Ming Dynasty loyalist Koxinga (Cheng Ch'en-Kung) successfully attacked the Dutch in the South of Taiwan, the crew of the Keelung forts fled to the Dutch trading post in Japan. The Dutch came back in 1663 and re-occupied and strengthened their earlier forts. However, trade with China through Keelung was not what they hoped it would be and, in 1668, they left voluntarily.
In 1863, the Qing Empire opened up Keelung as a trading port.
The Keelung Campaign was an important subsidiary campaign in the Sino-French War (August 1884 to April 1885). The French occupied Keelung from 1 October 1884 to 22 June 1885, and several battles were fought during this period between Liu Ming-ch'uan's Army of Northern Formosa and Colonel Jacques Duchesne's Formosa Expeditionary Corps.
A systematic city development started during the Japanese Era, after the 8 May 1895 Treaty of Shimonoseki, which handed all Taiwan over to Japan, went into force. A five-phase construction of Keelung Harbor was initiated, and in by 1916 trade volume had exceeded even those of Tamsui and Kaohsiung Harbors to become one of the major commercial harbors of Taiwan.
Keelung became a town in Keelung District, Taipei Prefecture in 1920 and was upgraded to a city of Taipei Prefecture in 1924.The Pacific War broke out in 1941, and Keelung became one of the first targets of Allied bombers and was nearly destroyed as a result. Coal mining
