Oga is a city located in Akita Prefecture, Japan. As of 28 February 2023, the city has an estimated population of 24,687 in 12,496 households, and a population density of 100 persons per km2. The total area of the city is 240.80 square kilometres (92.97 sq mi).

Akita Prefecture [a̠kʲita̠] is a prefecture of Japan located in the Tōhoku region of Honshu. Its population is estimated 915,691 and its geographic area is 11,637 km2. Akita Prefecture is bordered by Aomori Prefecture to the north, Iwate Prefecture to the east, Miyagi Prefecture to the southeast, and Yamagata Prefecture to the south.