景行天皇
The origins of the name Ōita are documented in a report from the early 8th century called the . According to the document, when Emperor Keikō visited the Kyushu region, stopping first in Toyo-no-kuni, he exclaimed that 'This is a vast land, indeed. It shall be known as Okita-Kuni!' Okita-Kuni, meaning "Land of the Great Fields", later came to be written as "Ōita". Present day interpretations based on Ōita's topography state that Oita's name comes from "Okita", meaning "many fields", rather than "vast" or "great" field, because of Ōita's complex terrain.