The area of Usa was the southeastern tip of the former
Buzen Province and on the border with the former
Bungo Province. The name "Usa" appears in the
Kojiki and
Nihon Shoki and
Emperor Jimmu visited Usa prior to departing to the east for his conquest of
Yamato. Due to the economic and political power of Usa Jingū, no
samurai clan was able to dominate the area until the
Sengoku period during which time it became a battleground between the
Ōuchi clan and
Ōtomo clan and later the
Shimazu clan. Under
Toyotomi Hideyoshi, Buzen province became the territory of
Kuroda Yoshitaka, who constructed
Nakatsu Castle. During the
Edo period it was mostly
tenryō administered directly by the
Tokugawa shogunate, with smaller areas under control of
Nakatsu Domain,
Shimabara Domain and Usa Jingū. After the
Meiji restoration, the town of Usa within
Usa District, Ōita was established on May 1, 1889 with the creation of the modern municipalities system. On April 1, 1955 Kitsuki merged with the villages of Yasaka, Kita-Kitsuki and, Nakarie and was raised to city status. On October 1, 2005 Kitsuki merged with the town of Yamaka from Hayami District and the village of Ota from
Nishikunisaki District, Ōita. On April 1, 1967 Usa merged with the towns of Ekigawa, Yokkaichi, and Nagasu to form the city of Usa. On March 31, 2005, the towns of
Ajimu and
Innai (both from
Usa District) were merged into Usa. During
World War II, the Usa Naval Air Group (
宇佐海軍航空隊,
Usa Kaigun Koukūtai) was stationed at an airbase in Usa. Towards the end of the war, the airbase was used to launch
kamikaze attacks against American forces. It was subject to
B-29 air raids in 1945 which led to the destruction of many of the airfield's facilities and caused the deaths of many soldiers and civilians. bunker at the former Usa airbase ==Government==