Okazaki is a city located in Aichi Prefecture, Japan. As of 1 October 2019, the city had an estimated population of 386,999 in 164,087 households, and a population density of 999 persons per km². The total area of the city was 387.20 km2 (149.50 sq mi).

Okutono Domain , also known as Okudono, was a feudal domain under the Tokugawa shogunate of Edo period Japan, located in Kamo District and Nukata Districts of Mikawa Province, and in Saku District, Shinano Province, Japan. The domain was also known as Ogyū Domain and later known as Tanoguchi Domain and Tatsuoka Domain . The ruling family was the Ogyū-Matsudaira clan.